How to Remove Soap Scum From Shower Doors. Soap scum is a white, waxy build up that forms on your tiles and doors. In combating soap scum on shower doors, an ammonia solution has the double advantage of being both an effective glass cleaner and a strong all-purpose cleaner. Here are a few easy steps to get your shower doors looking good as new. Read more: http://www.ehow.com/video_3149_remove...