Guess what? Lye soap has been used for hundreds of year to get tough stains out of laundry. Even today, soccer moms are trying to find it because it gets out those terrible grass stains in soccer shorts. It gets out other tough stains, too. Lye soap comes as a bar for personal use. Lye soap has proven useful for washing when you have psoriasis or eczema. The bar can be rubbed into laundry stains or used to wash skin.