7. Remove excess grout. After 10 minutes, wipe off the excess grout with a tile sponge. Rinse the sponge in clean water after each pass. When the surface dries, wipe off the final haze with a soft cloth, or use a solution of water and vinegar. Dispose of the water outdoors; grout deposits can clog waste lines.

8. Seal and caulk. Apply grout sealer with a stiff-bristle brush after grout dries for 3 days. Wipe off any sealer that lands on the tile. Apply a double strip of masking tape where the countertop meets the tile. Fill in the joint with caulk. Smooth it with a wet finger. Let caulk dry, then peel off the tape.