To remove a peephole, gather tools like screwdrivers and pliers. Identify the type of peephole and its components (housing, lens, retainer, screw). Use a screwdriver to remove the retaining screw. Grip the housing with pliers and pull it out gently. Inspect the lens and retainer for damage. If necessary, replace the lens by unscrewing the retaining ring and inserting a new lens. Reassemble the peephole by inserting the housing, lens, and retainer into the door hole. Tighten the retaining screw to secure the peephole. Consider consulting a locksmith for professional installation or maintenance if needed.