"The fats and oils in soaps create problems with soap scum," Lynn Marie Bower tells Housekeeping Channel. But since body wash is technically a detergent, it's specifically formulated to prevent gross crud from caking up in the shower.
How to remove printing from containers! Wearing gloves, saturate cleaning rag in acetone (found near the nail polish remover in stores) and then wrap around plastic container. Keep it wrapped for 3 - 5 minutes.