A lot depends on the surface you're cleaning. I use soft scrub w/bleach on just about everything. Most of the tough scum comes up with little effort. My shower is ceramic tile/tub. When we were building this house, the concept of fiberglass surrounds was mentioned. Got a resounding 'no' from me due to prior experience. It was recommended that if that is your situation, after getting it clean, use general car wax on the fiberglass.