Ok, so I'm still looking for the great all-purpose cleaner.  What's my answer?  Like we said, there isn't one, but you can clean almost anything with a few simple household ingredients.  Here they are:

Alkaline Cleaners for Greasy Stains:  

Ammonia - (NH3)  We all know the distinctive smell of ammonia.  It is the active ingredient in "smelling salts" and the odor of window cleaners such as Windex^®.  Ammonia is a weak base in water.  Used in many commercial and homemade cleaners, it is an excellent all-purpose grease cutter, wax stripper, and window cleaner.  

How it Works:  Because most greasy stains tend to be slightly acidic, ammonia (a base) neutralizes them and loosens the stain in general.  Also, the reaction of many food stains (often just fatty acids) with ammonia actually creates small amounts of soap through saponification.  This soap can then aid in the emulsification (breaking-up of) of the fats and oils that are present in many soils or films.  Ammonia makes a great window cleaner because it evaporates very rapidly and leaves less streaks.

Tip:  If you don't feel like diluting your own ammonia to make a homemade cleaner, a bottle of generic window cleaner is affordable and is basically just:  ammonia + water + a spray bottle.  We do not recommend using this type of ammonia, however, with the homemade cleaners later this document.  Commercial window cleaners may have extra ingredients not labeled on the bottle that may react adversely when mixed.

Cautions:  Inhaling concentrated ammonia can cause breathing problems, lung-tissue damage and even cancer.  NEVER MIX WITH BLEACH!

Bleach - (Sodium Hypochlorite/NaOCl)  Bleach, as we all know, is great for whitening anything, removing molds and mildews, and general cleaning.  Of course it's also a bit nasty to use and not very environmentally friendly.

How it Works:  Bleach contains chlorine which kills bacteria, algae, molds and mildews by disrupting important cell functions.  Bleach bleaches because of it contains oxygen.  When it reacts with water it creates--among other things--atomic oxygen (O₂).  The oxygen, in turn, reacts with the color-forming molecules of your stained-substance.  It disrupts the chemical bonds and creates new bonds that absorb a different wavelength of light, hence turning it white.  Other chemicals that bleach (such as hydrogen peroxide and borax) also contain oxygen and will bleach stains/materials by the same chemistry.  For more information see: Bleaching Agents and  How Bleaching Works.

Cautions:   Always use in a well ventilated area.  Drinking bleach is deadly.  Excessive inhalation can cause serious health problems.  DO NOT MIX BLEACH WITH ANYTHING, ESPECIALLY:  VINEGAR, TOILET BOWL CLEANER, OR AMMONIA.  Bleach and ammonia produce the deadly gas, chloramine.  Bleach and toilet bowl cleaners, vinegar and other acids produce a deadly chlorine gas (this chlorine gas is also formed by bleach reacting with air and water but the acids make the reaction go faster). 

Baking Soda - (sodium bicarbonate/NaHCO₃).  Baking soda is made by bubbling carbon dioxide through soda ash or washing soda (sodium carbonate).  Extremely versatile, baking soda is an all-purpose, nontoxic cleaner. It cleans, deodorizes, scours, polishes and removes stains.  There's so much information on the uses of baking soda for cleaning, it would be impossible to list them all here.  For 51 uses see:  The Baking Soda Page.

How it Works:   Baking soda acts as a cleaning agent because it is a mild alkali and can cause dirt and grease to dissolve easily in water. When it is not fully dissolved, like when it is sprinkled on a damp sponge, baking soda is mildly abrasive and can lift dirt for easy removal as a gentle scouring powder.   Baking soda’s deodorization power is a result of its ability to neutralize odors, rather than just covering up odors with perfumes. Most unpleasant odors come from either strong acids (like sour milk) or strong bases (spoiled fish). Although baking soda is a base, it is also a buffer which means it not only neutralizes strong acids, but it can act as an acid around stronger bases, bringing them into a more neutral state.  Therefore, baking soda deodorizes by bringing both acidic and basic odor molecules into a neutral, more odor-free state (although it does tend to work better on acidic odors that basic ones). 

Cautions:  None.  You can eat it.  Although more than a few teaspoonfuls will make you sick.  Bleck...who'd want to try that?

Borax  - (sodium borate/Na₂B₄O₇ • 10H₂O) Borax is a natural mineral and was discovered over 4000 years ago. Borax crystals are white, odorless and alkaline/basic.  Borax has been used for many years in the house as a laundry booster (makes soap more effective), a multipurpose cleaner, stain remover, a fungicide and a disinfectant.  Because borax has bleaching and antibacterial properties it can be a great alternative for those who do not want to use bleach.

How is Works   Borax cleans and bleaches by converting some water molecules to hydrogen peroxide (H₂O₂) especially in hot water.  Borax produces a basic solution in water, helping to neutralize acidic food stains.  The boron, salt, and/or oxygen of boron inhibit the metabolic processes of many organisms. This characteristic allows borax to kill unwanted pests and bacteria.  Borax acts as a chelator (bonds with minerals to reduce the hardness in water), which maximizes the available soap and enhances cleaning power.

Risks Associated with Borax  Borax is non-flammable and non-reactive.  It can be mixed with almost any other household chemical (though we don't suggest experimentation).  However, like many other household cleaning products borax is poisonous.  It can be used to kill roaches, ants and fleas.  More than 5 grams can also kill a child and cause severe health problems or death in adults.  Rinse all surfaces well after using borax, and do not use around food.

Soap - (a fatty acid salt, chemical formulas vary depending on the fatty acid and base used to create it. Example:  3CH₃(CH₂)₁₄CO₂Na).  Soap, as we all know, cleans just about anything and is mild.

How it Works:  Soap is mildly alkaline and has surfactant properties.  

Cautions:  Well, don't eat it, obviously.  Otherwise it's pretty safe to you and friendly for the environment.

Washing Soda/Soda Ash - (sodium carbonate/Na₂CO₃)  Can be used as a wax stripper, grease cutter, soap-scum remover, disinfectant, deodorizer and even petroleum stains.  It makes soap more effective.  Washing soda is much more alkaline than baking soda and can be used for tougher stains, but is also more caustic and less safe than baking soda.

How it Works:  Washing soda works in much the same way as baking soda.  However, it is a much stronger base allowing it to be useful for more hard-core cleaning (i.e. wax stripping).  It will also increase the cleaning power of soap by acting as a chelator (removing the hardness of water by tying up mineral deposits).  Of course it is also harder on surfaces than baking powder.

Cautions:  Wear gloves.  It is basic/alkaline enough to burn the skin on your hands.  Washing soda is NOT edible and cannot be used in baking.

Acidic Cleaners for Inorganic Stains:  

Lemon juice - (Citric acid, C₆H₈O₇).  Great for cleaning metals, but vinegar is cheaper.   It  cuts through stains on aluminum, cleans bathroom and kitchen fixtures and porcelain.  Also leaves behind that nice lemon scent.  

Vinegar  - (Vinegar is diluted acetic acid, CH₃COOH).  Very cheap and versatile, great for cleaning hard surfaces and windows, and shining up metal surfaces. Removes mildew, stains, certain grease and wax buildup.  Baking soda and vinegar are certainly the two most multipurpose household cleaners.  You can clean almost anything with just these two chemicals and water. 

Ketchup - (Contains Citric acid, C₆H₈O₇). Good for cleaning copper and brass.

How Acids Clean:   When metals react with oxygen in the air, a rust/corrosion film occurs:

Fe⁺² + O₂ +   H₂O ® Fe₂O₃ + H^{+
iron + oxygen + water ---> rust + hydrogen}

Acids clean metals because they react with the rust/corrosion that has occurred on the metal's surface to form water and a metal-containing bi-product (the bi-product depends on the acid used). Some acids produce bi-products--such as iron phosphate--that actually protect the metal from further oxidation by forming a protective coating (see below). 

Fe₂O₃ + 2 H₃PO₄ ® 2 FePO₄ + 3 H₂OFe₂O₃ + 2 H₃PO₄ ® 2 FePO₄ + 3 H₂O
rust + acid --> bi-product (iron phosphate forms a protective coating) + water

Other acids such as vinegar may not form such a protective coating and may actually cause more rust if not rinsed off after the cleaning procedure.  For more information see:  Corrosion and Using Vinegar For Cleaning.

Acids also react with mineral deposits, and kill bacteria and mildew.

Cleaners for Petroleum-Based Stains:

Rubbing Alcohol (CH₃-CHOH-CH₃) and Hairspray (denatured alcohol)- Like water rubbing alcohol is a neutral solution, but works better than water for cleaning in some cases.  It evaporates quickly (leaving no residue), is mild, and can be used in cleaning things that aren't supposed to get wet.  And, of course, rubbing alcohol is a disinfectant.   Rubbing alcohol works well on ink stains.  If not, try denatured alcohol (hairspray).  Rubbing alcohol will clean the caulking around bathtubs. It also shines chrome and glass. 

Fingernail Polish Remover - (acetone, dimethyl ketone, 2-propanone, C₃H₆O)
Lighter Fluid - (kerosene, varies in carbon content between 9 and 17)
Paint Thinner - (mineral spirits, complex petroleum distillate)
Turpentine - (Oil of Turpentine, C₁₀H₁₆)    - All of the above solvents are petroleum-based and highly flammable.  Different ones might work better in different situations depending on the stain and the material being cleaned, but all should work well to take out such things as:  tar, paint, motor oil and axle grease.

Peanut Butter, Baby Oil, Cooking Oils, Mayonnaise and Salad Oil - These non-water solvents can be used as a safer substitute for the above solvents in many cases.  They work especially well for cleaning your hands after working on the car or getting gum and other sticky stuff out of hair. 

Other Cleaners: 

Salt - Regular table salt makes an abrasive, but gentle, scouring powder.  Like baking soda and vinegar there are hundreds of little-known household uses for salt.  For a list of some of these see:  Salt Use Secrets.

Hydrogen Peroxide (H₂O₂) Yes, the stuff in the brown bottle.  Besides being an antiseptic, it is also a bleach and so can be used for certain cleaning tasks.  The bubbling action that occurs when it comes in contact with certain stains helps lift out stains in the same way that commercial foaming cleaners work.  Peroxide is often recommended to clean blood, but remember it will also bleach your carpet if you aren't careful.

Cautions:  Hydrogen Peroxide is fairly safe for you and the environment, although large doses or concentrations when ingested can be harmful.   

Shaving Cream and Meat Tenderizer -  Shaving cream works wonders as a foaming carpet cleaner.  Meat tenderizer will sometimes work on stains that would otherwise require a commercial enzyme-digester (i.e. vomit and urine).  Simply sprinkle it on, let set, vacuum and sponge off with clean water.  But watch out!  Some meat tenderizers have a reddish dye in them that is really hard to get out.

More Complex Homemade Cleaners

All Purpose Cleaners

2 cups rubbing alcohol (70% isopropyl)
1 tablespoon mild dishwashing liquid (for hand washing dishes, NOT dishwasher detergent-it contains bleach!  Bleach + Ammonia is very very bad!)
1 tablespoon household ammonia
2 quarts water

1/4 cup baking soda 
1 tablespoon household ammonia (optional)
1/2 cup white vinegar
1 gallon warm water

2 teaspoons borax
1 teaspoon  baking soda 
1 quart of water.

Mix ingredients and store in new spray container.  Use with a cloth or sponge to clean the bathroom fixtures, kitchen fixtures, appliances, chrome, plastic countertops, and painted surfaces. Rinse with a clean cloth or sponge after cleaning.  

The Lazy Solution to Cleaning Everything (Almost)

If you don't feel like mixing ingredients, simply using baking powder and water as a general scouring cleaner and pour diluted vinegar over it for the tougher stains.  Let the vinegar/baking powder mixture set for a while if the stain is not coming off right away.  Use vinegar and water for windows, glass, and chrome.  You can clean almost your whole house with just vinegar, water and baking soda.   Always wipe with water and dry with a clean cloth after using any cleaning chemical, including these homemade solutions.  See the Baking Soda and Vinegar page for more ideas on the household uses of these two products.  

Interesting Note:  Why are we mixing an acid and a base in some of the above methods?  (i.e. ammonia and vinegar / vinegar and baking soda)  Doesn't that neutralize the solution and defeat the entire alkaline/acidic-cleaner theory discussed earlier?  

Answer:  When you neutralize an acid with a base, one does not only end up with water.  In our above solutions, there's other stuff floating around other than protons (H⁺) or hydroxide (OH^-). In the vinegar/ammonia example there's going to be a mixture of acetic acid and acetate (both from the vinegar) as well as other things, and NH₃ and NH₄⁺ (from the ammonia). What you've basically got is a buffer solution.  A buffer solution is a solution that is only slightly basic or acidic and so tends to bring highly acidic stains/odors back towards a more basic state and highly basic stains/odors towards a more acidic state.  In this way a buffer solution helps to neutralize both acidic and basic stains.  In our example of ammonia and vinegar, the solution will also have lots of ions (charged particles) floating around which will help dissolve charged dust particles and other compounds which will help dissolve organic muck.

Furniture Polish

1 cup vegetable oil (try other cooking oils as you prefer)
1/2 cup lemon juice

Pour oil and lemon juice into a squirt bottle or jar. Stir to combine. To use, dip a dust cloth or rag into oil, blot the oil by folding the cloth together.  Wipe your wood furniture. 

Carpet Cleaner and Deodorizer 

Sprinkle baking powder over the carpet (add borax if you desire and if you are not worried about pets or children getting into the powder while it is setting), let set, then vacuum.   Use shaving cream as a foaming carpet cleaner to get out the spots.  Meat tenderizer will also work on certain tough spots.  Sprinkle, let set, sponge off with clean water.

Drain Cleaner 

Once a week, pour 1/4 cup baking soda, then 1/2 cup vinegar. This will fizz, but the bubbling action will help lift and dissolve dirt.  Wait 20 minutes; then pour 1 gallon boiling water.

How it Works:  The baking soda will help dissolve soap-scum and grease, the vinegar will help burn away mineral deposits and scale.  The reaction that goes on when the two mix is as follows:  the acetic acid in the vinegar (CH₃COOH) and the baking soda (NaHCO₃) react to create sodium acetate (a salt:  NaC₂H₃O₂) and carbonic acid (H₂CO₃).  The carbonic acid breaks down into water and carbon dioxide (CO₂).  The carbon dioxide (the same stuff that makes your sodas fizz) is what creates the fizzing and helps lift the dirt.  Assuming you do not use extremely concentrated acetic acid or actually drink your homemade Draino this reaction is a safe one and produces bi-products safe for the environment.

Scouring Powder

Use Bon Ami or salt or baking soda.

Window and Glass Cleaner

1/4 cup white vinegar (or vinegar and ammonia)
1 quart of water

Metal Polish

1 tablespoon flour
1 tablespoon salt
1 tablespoon white vinegar

Combine salt and flour in small bowl (or just baking soda and water) and stir until blended. Add the vinegar and mix into a thick paste. Smear on the paste with a damp sponge or cloth and rub gently. Let the polish dry for about an hour. Rinse well with warm water and buff dry with a soft cloth.

References:

About.com--Soap and Saponification;  How Does Soap Clean;  How Does Borax Clean
Allabouthome.com--Cleaning Tips
Chemistry.co.nz--Detergent Info
Kcpc.usyd.edu.au--Soaps
Madsci.org -- Search the Archive
Newton.dep.anl.gov -- Search the Archive
Pathtofreedom.com--A Guide to Homemade Cleaners
Sciencenet.org.uk--Search Science Net Archive
Suncitysoap.com -- Understanding Commercial Soaps and Detergents

Content writing and research done by Freelance Writer Wintress Odom.