Dark Stains in Shower Caulk and Tile Grout: Lift, Dry, Prevent

Clean first, the plain way

Start with soap and water. The EPA's cleanup advice for hard surfaces is short:

What that does not shift is the dark staining inside the caulk and the grout. That is where a gel helps.

Using a gel on caulk and grout

Dry the line completely. Lay the gel on thick along the caulk bead or the grout joint. On a wall, choose a gel that clings, and for the highest joints press a paper towel soaked in gel against the line.

Leave it for the time on your bottle, then wipe away with a damp cloth. Deep, old lines often need a second round.

When to replace the caulk instead

Caulk that is cracked, lifting at the edge or soft to the touch is past cleaning. Cut it out, let the joint dry for a day and run a new bead. One thing you should not do:

• Cracked or peeling caulk: replace it
• Dark marks under intact caulk: gel, then keep it dry
• Marks on grout: gel, then seal the grout once it is clean and dry

Keeping the bathroom dry

Ventilation matters more than which cleaner you use:

Run the fan during every shower and for twenty minutes after. Squeegee the tiles. Leave the shower door open.

What a gel is not for

Soft, absorbent materials are a different problem:

This guide is general information about cleaning. It is not medical, legal or safety advice.