Ammonia is a toxic, corrosive, and pungent compound gas (nitrogen and hydrogen) diluted with water. It's alkaline, aka basic, which means it's excellent at eating away grease, oil, fat, and other protein-base stains high in fatty acids. Being a gas, it evaporates quickly and without residue. Keep in mind that ammonia should never be mixed with bleach.
Baking soda, aka sodium bicarbonate, is a nontoxic base, which means it excels at attacking greasy (fatty acid) residue. Since it comes in powder form, it's an excellent absorbent, too. When combined with an acid, like vinegar, it forms a bubbling, reactive solution.
All-purpose bleach is made up of a host of chemicals, including chlorine, that together form a highly basic (aka alkaline) -- therefore highly corrosive and toxic -- solution. Bleach effectively kills bacteria, fungus, and color-causing chromophores through a chemical process known as oxidation. This bacteria-slayer should never be combined with ammonia or vinegar.
Dry-cleaning fluid is a readily available consumer version of your local dry-cleaner's waterless liquid solvent. It's generally stable and nonflammable, yet toxic, and excellent at degreasing and dissolving organic and water-resistant stains on a wide variety of fabrics.
Hairspray works as a stain remover in a pinch, as a stand-in for rubbing alcohol (see below), a nonpolar agent that dissolves other nonpolar substances, such as dyes, fats, and sticky residues. Of course, this is only the case if your hairspray contains alcohol. Many today contain little to none, since alcohol is extremely drying.
Hydrogen peroxide is water with an extra oxygen molecule. That makes it a weak acid and an excellent oxidizer, which means it oxidizes, or kills, bacteria -- that's what's happening when you see that foaming action. It does the same to color, making it a good, nontoxic bleach alternative. Just be sure to keep it in a dark bottle, as light renders hydrogen peroxide ineffective.
These sponges are actually a special type of melamine resin foam. The "magic" happens in two parts: The foam's surface essentially works as a superfine sander, while its interior bubbles soak up stains.
Natural Enzyme Cleaner
Enzymes are protein molecules, found in every living thing, that speed up natural processes, such as biodegradation. They help quickly and naturally return organic matter, such as fats, foods, oils, and bodily fluids, back to basic elements.
Rubbing alcohol is a neutral yet toxic solvent made up of nonpolar molecules, which dissolve other nonpolar substances, such oils, fats, dyes, and more. Because of rubbing alcohol's neutrality, it can be tough on stains but remain soft on surfaces. It also works as a disinfectant, basically dehydrating bacteria to death. This extreme drying power helps it evaporate quickly, too.
Made by fermenting grain, white vinegar is nontoxic and biodegradable. It's also an acid, which means it naturally breaks down dirt, grease, minerals, and bacteria. Never combine vinegar and bleach.