Blot the stain with a wet rag if the puff paint is still wet. Blot away as much of the puff paint as possible before it dries.
Spray hairspray on the puff paint if it is dried and rub the fabric together vigorously. This should start to remove some of the puff paint. Spray more hairspray and continue to rub the fabric together until the majority of the puff paint is removed. Wipe away the last remnants of puff paint with a wet rag.
Apply mineral spirits to a rag and blot it on the paint-stained fabric. This is a last-resort scenario and should only be used if the stain will not budge. Be sure to use mineral spirits in a well-ventilated room and wear rubber gloves and a face mask.