Are you referring to grout sealer? I wipe it off immediately. Currently I am using Dupont grout sealer which I buy at Lowes. Before that I used Aqualab which Lowes quit carrying. I like them both. Once I bought some grout sealer at a garage sale, a brand I had not heard of, and when I used it, it Instantly formed a film that I could not remove; I would have literally had to grind it off. So now, if I tried another brand, I would test it first. Here's how I apply grout sealer. I decant some of it into a spray bottle and spray the mosaic, then wipe off. I pour the unused portion back into the container and I rinse my spray bottle well, including clearing the nozzle. This is an easy and economical way to apply grout sealer.