Spots that are not immediately removed can turn into permanent stains very easily. When a carpet is new or has sufficient protector on it, plain tap water will remove many spots. However, for those spots that will not move easily with water, you must use a spot cleaner. Select a spot cleaner that is recommended by the carpet manufacturer or your trained, certified professional cleaner. Most spot removers that are purchased over the counter leave too much soap residue and can cause yellowing. Avoid using foam carpet cleaners or any product that is not made specifically for carpet.
Apply spot cleaner sparingly to white terry cloth and gently massage spot causing it to transfer into the cloth. Never pour spot cleaner directly on carpet. If the product that you are using seems to cause the spot to re-soil over a few week period, discontinue use. Any spot that you are not able to remove, and for pet urine or feces, call your professional cleaner immediately.