How do you fix the problem when the old grout has turned gray and ugly?
I am renovating my bathroom. The old tiles on the walls are in good condition, but the grout lines are gray and I want to make them white.
I don't want to apply grout – it would fall off, and I was offered to paint with a special grout pen. Who has used it and can tell me if it meets my needs? I was also thinking of trying silicone caulk or silicone paint.
Silicone will darken and then turn black. Remove the old grout and apply new grout.
Choose epoxy or polymer grouts that are highly resistant to moisture, deformation and abrasion.