How to Remove Cured Silicone Caulk

Silicone caulk is an excellent sealant, but over time it will need to be replaced.
Silicone caulk is an excellent sealant, but over time it will need to be replaced. (Image: glazier image by Greg Pickens from

Silicone caulk, used in areas exposed to water and moisture, has a tendency to grow mold and mildew. Some silicone caulks even have organic ingredients that mildew eats. Mildew- and mold-resistant silicone caulk have been developed and if you want to use them, you must remove the old silicone caulk first. The task of removing the old silicone caulk is taxing and dangerous to your digits so you must wear protection on your hands.

Things You'll Need

  • Razor blade
  • Medium weight work gloves
  • Sodium or potassium hydroxide
  • Scouring powder
  • Sponge

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Scrape away the bulk of the caulk with a razor blade. Scrape off the caulk in long strips if you can to simplify the job.

Lubricate the caulk and the blade with water. Scrape along the silicone caulk slowly; remember the more power you exert, the less control you have over the blade. There will be small remnants of caulk left over.

Mix sodium or potassium hydroxide with water. Apply it with a sponge to the caulk area to dissolve the remnants, and let it rest for a minute before wiping it off. If you leave it on too long, it will damage the surface under the silicone caulk.

Sponge the area with scouring powder and water to remove the scratch marks on the surface from the razor.

Tips & Warnings

  • Wear medium weight work gloves in order to protect your fingers and hands from the razor blade.


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