33+ How To Clean Glass Shower Doors With Hard Water Stains. For tough hard water stains, add some ammonia to your cleaning mixture. Hard water stains appear as white, hazy spots on glass surfaces.
The harder the water, the harder it will be getting glass shower doors clean.
An employee who worked at a car stereo/tint store told me they used soft steel wool and car polish on stained car windows. If the door is clean, and all surface residue has been removed, you can apply lemon oil to the dry the doors off after each use to keep soap scum and hard water stains from returning. Vinegar (inside of a spray bottle), paper towels, and a squeegee. To further prevent hard water spots, spray the shower doors with a water repellent.