Posted 01 May 2011 - 10:30 PM
I disagree with everyone that says seal it, I have seen more bloched seal jobs than problem free ones. To seal the stone it has to be 100 percent dry or the moisture will try to push through the sealer, and if that happens it is nealer impossible to remove the sealer. And as an added plus you have seal it every couple years. It is just asking for problems especially in a shower, moisture + sealer = bad. If you have slate actual real stone not proclein that looks like stone you can use muriaic acid, dilute with water a be careful very caustic, and vent the room. We do alot of slate patios and outdoor kitchens with slate tops. The muraic acid helps clean the stone from any motar scum and makes it more crisps. But beings it is inside I would use acid as a last resort. Hope this helps.