Drains may become clogged by objects dropped into them or by accumulations of grease, dirt, or other matter.
If the obstruction is in a fixture trap, usually the trap can be removed and cleared. If the obstruction is elsewhere in the pipe other means must be used.
Cleanout augers—long, flexible, steel cables commonly called "snakes"—may be run down drainpipes to break up obstructions or to hook onto and pull out objects. Augers are made in various lengths and diameters and are available at hardware and plumbing-supply stores. (In some cases, you may have to call a plumber, who will probably have a power-driven auger.)
Small obstructions can sometimes be forced down or drawn up by use of an ordinary rubber force cup (plunger or "plumber's friend").
Grease and soap clinging to a pipe can sometimes be removed by flushing with hot water. Lye or lye mixed with a small amount of aluminum shavings may also be used. When water is added to the mixture, the violent gas-forming reaction and production of heat that takes place loosens the grease and soap so that they can be flushed away. Use cold water only. Chemical cleaners should not be used in pipes that are completely stopped up, because they must be brought into direct contact with the stoppage to be effective. Handle the material with extreme care and follow directions on the container. If lye spills on the hands or clothing, wash with cold water immediately. If any gets into the eyes, flush with cold water and call a doctor.
Sand, dirt, or clothing lint sometimes clogs floor drains. Remove the strainer and ladle out as much of the sediment as possible. You may have to carefully chip away the concrete around the strainer to free it. Flush the drain with clean water.
When drains have become partially clogged due to lack of water to transport all solids through them, large buckets or other containers should be used to flush them. Water should be poured fast enough to nearly fill the drain.
Occasional flushing of floor drains may prevent clogging.