Is the caulk around your sink and tub discolored? It’s likely mold and mildew. To get rid of it, take an X-ACTO knife and cut out the old caulk.

“Don’t go over dirty caulk,” warns Rea. “And don’t use too much pressure with the knife. You don’t want to leave a mark on the tile.”Fill the gap with 100% silicone-based caulking. It’s water-resistant and durable. Smooth it out with your finger, and clean up any excess as you go. –Marc Freeman