Fireplace Cleaner 4 ounces naphtha soap 1/2 pound powdered pumice 1 quart hot water 1/2 cup household ammonia Add soap to the hot water. Heat until the soap dissolves. Cool, then stir in pumice and ammonia. Mix thoroughly. Remove as much of the smoky deposit as you can before applying a coat of the soap mixture with a paint brush. Allow it to remain on for 30 minutes. Scrub with a paint brush and warm water. Sponge with plenty of water to rinse.