DIY
Sprinkle baking soda on carpets, wait 15 minutes, then vacuum. Attend to spills as quickly as possible by blotting the wet area with clean, white cotton towels. Continue until nearly dry. If necessary, apply a spot-cleaning solution of clear dishwashing liquid and water (about 1/4 teaspoon per quart). Rinse well and blot to dry.

Tips
When deep-cleaning is necessary, look for professional carpet cleaners who use less-toxic brands (most manufacturers make professional-only products, since the formulations require high-end machinery to use).