You probably never thought the soap you use to wash your hands could be causing your drain to clog, but it can. Soap is made up of oils and fats, which can solidify and cling to the sides of your pipes. Over time, this build-up can cause a blockage. There are a few things you can do to prevent this from happening. First, invest in a drain strain to catch the soap before it has a chance to enter your pipes. Second, switch to liquid soap instead of bar soap. This will help reduce the amount of build-up in your pipes.