Step 3 · Clean the Sink Drain Opening
After removing the old strainer, thoroughly clean the area around the sink drain opening on both the top and bottom surfaces. Use a plastic putty knife to scrape away all the old plumber's putty or sealant residue. Be careful not to scratch the sink surface. Once the bulk of the old putty is gone, use a non-abrasive scouring pad and a mild cleaner or mineral spirits to remove any remaining film, then wipe the area dry with a clean cloth. A perfectly clean, dry surface is essential for a good seal.