The silicone line around my tub has black spots that won't scrub off. Bleach makes it lighter but it comes back. Do I have to redo it?
How do I get rid of black mold in my shower caulk?
Concerns & risks
You scrub the shower every week, but those black lines in the caulk won't budge. Bleach lightens them a little and they come right back. It makes a clean bathroom look dirty.
It looks dirty no matter how much you clean, and the gap can let water behind the tub.
Causes & evidence
Mold grows into soft silicone that stays damp after showers. Why moisture matters: moisture and mold.
What to do
- Cut out the old caulk with a utility knife or caulk remover tool.
- Clean the joint, then let it dry fully (24 hours is ideal).
- Run a bead of 100% silicone labeled for kitchen and bath, mold-resistant.
- Smooth it with a wet finger, wait the cure time on the tube before showering.
Common mistakes: Applying new caulk over old moldy caulk traps the problem. Remove it fully, clean and let the area dry completely before recaulking. Never mix bleach with ammonia or acid cleaners. Ventilate while cleaning. And don't skip running the fan after showers, or the new caulk will grow the same spots.
Speed Man tip: Squeegee the walls after showers and run the fan 20 minutes. Your new caulk will stay white much longer.
Wrap-up: Black spots inside caulk won't scrub out; replace the caulk. Remove, dry fully, re-caulk with mold-resistant silicone. Squeegee and ventilate to keep it clean.
⚡ Speed Summary
- Black spots inside caulk won't scrub out; replace the caulk.
- Remove, dry fully, re-caulk with mold-resistant silicone.
- Squeegee and ventilate to keep it clean.
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