Baking Soda

• Baking soda is useful for removing tough carpet stains, but it also absorbs moisture and removes odor, making it especially beneficial. After drying up the surface moisture (for fresh spills), sprinkle some baking soda on the remaining dampness and blot with a damp cloth or sponge. For older set-in stains, you can sprinkle baking soda directly onto a damp cloth and work the solution into the carpet gently until the stain lifts.
  
  

Dish Detergent

• A mild dish detergent is useful for more than just plates and cups. Squeeze a drop into a cup of water, and dampen a cloth or sponge with the sudsy solution. Gently blot the stain with the detergent, then blot again with a second cloth (dampened with just water). Repeat with your first cloth, and continue in this fashion until the stain lifts. Try not to soak your carpet as carpets are extremely vulnerable to mildew and very difficult to dry once saturated.
  
  

Vinegar

• White vinegar is another useful tool to have in your carpet-cleaning arsenal. The acetic acid breaks up the residue and enables you to easily wipe the stain away. Vinegar can have a powerful effect, though, and you should not need more than 1 tbsp. of white vinegar to a cup of water. Good Housekeeping recommends adding a tbsp. of dish detergent to your solution for even greater effectiveness.
  
  

Dry Cleaning Solvent

• Dry cleaning solvent is useful for removing stains without saturating your carpet. If you live in an environment susceptible to mold, or if you just want to minimize your use of liquid, spray a dry cleaning solvent over your carpet stain, and dab with a lightly-dampened cloth. You can find dry cleaning solvents at home supply stores and some grocery stores.
  
  

Oxygen Bleach

• Oxygen bleach usually comes in a powdered form, so you will need to mix the crystals with water according to the manufacturer's directions. Apply directly to the stain, and blot gently with a cloth. Unlike traditional household bleach, oxygen bleach has no fumes or volatile compounds and is safe. It also has greater effectiveness due to its oxygen release and can help you to remove carpet stains when other solutions fail.