Have larger walk-in shower in master bath w/white subway, DalTile 4x12 and a good quality grout installed about 3 yrs ago....because the accent tile has Crema marfil (although been sealed w/quality product) I have avoided using any cleaners by just wiping/squeegee the walls but there is some scum on the bottom row of tiles....We use liquid Dove shower soap but had someone borrowed our house (this is in 2nd home) for almost 3 months when they were between homes and they might have used other products....

can anyone recommend a cleaner that won't start to discolor the grout? Our tile guy didn't recommend any particular brand/product when I emailed him but I don't want to use something that might cause problem....

I use a mix of denatured alcohol and distilled water on the glass portion as per the installer

would that work on the scum and not damage the grout?