Step 4 · Clean the Drain Opening and Threads
Once the old flange is removed, you will likely see a ring of old, hardened plumber's putty and other residue around the drain opening on the tub surface. Use a plastic putty knife to carefully scrape away all of this old material. Then, use a rag dampened with denatured alcohol or a mild solvent to thoroughly clean the surface where the new flange will sit. Also, use a separate rag to clean the female threads inside the drain shoe below. A clean surface and clean threads are critical for a proper, leak-free seal.