Many of the commercial carpet stain removers work well, but some are designed for particular types of stains, so read the label. Also, some will work better or worse on a particular type of carpet, so pre-test the product in an inconspicuous area. To do do this, apply several drops of the solvent to your carpet, then press a white cotton cloth on the area for fifteen seconds. Examine the cloth to see if there is color transfer from the carpet, and examine the carpet for color changes or other damage. If there is any color transfer or damage at all, try a different stain remover.