Sludge builds up easily in the drainpipes and it can cause the drains to flow slower, along with emitting a foul smell. Sludge is a product of different things going down the drain–toothpaste, food particles and maybe some grease. Mold and mildew can also cause sludge problems. If you use chemicals to clear away the sludge, they may eat holes in your pipes. Taking care of your drains will keep them running like they should.
Pour 12 oz. to 1/2 gallon of bleach into the drains. You can clean out all the drains at once, or do it in stages. Leave the bleach in the drains overnight. Do not pour any water through the drains. The bleach loosens and dissolves hair and sludge.