By the time you have set it up and heated it I would have done the job and be moving onto the next one. Scum & Hard water deposits from tile & grout and shower screens just comes straight off with a little diluted Aqua Mix Phosphoric Acid Substitute (Make sure you do not have acid sensitive stone or that is affects any metal fittings of course) and the cleaning is done with some Aqua Mix Heavy Duty Tile & Grout Cleaner. Any mould isa taken care of with LTP Mouldex
Kev Martin
Marblelife Ltd
Tiling Logistics