How to get dark buildup off bathtub caulk
Persistent dark buildup along bathtub caulk often resists heavy scrubbing with standard foaming cleaners because it is deeply embedded or trapped beneath the seal. Trying to clean or replace the caulk without addressing the underlying accumulation leaves the film behind, leading many to mistakenly believe the discoloration is permanent or structural.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Asking apartment maintenance to take a look
- 2Scrubbing with a rag and scrubbing bubbles foamer
- 3Attempting to scrape the edges with a caulk tube and a scraper
- 4Leaving shims in place and caulking around or over them.
- 5Soaking the buildup with CLR using a paper towel for 24 hours and chipping it away with a plastic scraper
- 6Scraping out the entire corner substance and replacing it with caulk
- 7scraping off all the old caulk, cleaning the surface with alcohol, ensuring it is completely dry, and letting 100% tub and shower silicone cure for at least 12 hours
- 8Using a plastic putty knife to scrape the buildup off
- 9Scraping away old caulk, cleaning with alcohol, and applying new silicone.
- 10Calling the landlord to replace the affected sink part.
- 11Scrubbing until nothing comes off
- 12Filling up the tub so it is under load when caulking
- 13Removing old grout, spraying bleach, letting it sit, cleaning dry, and applying silicone caulk
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“Hello everyone, new bathtub, less than 4 months, and we noticed some holes and dark spots on the original caulking.”source ↗
“I scraped everything, cleaned with alcohol and applied new silicone. It didn't last couple weeks when the dark spots returned and now looks like shit again.”source ↗
“I just started using a plastic putty knife to scrape this yellow stuff off my shower walls, but I’m worried I also scraped the paint off.”source ↗
“Every few months, this darker kind of tan film starts to collect around the edges of my bath-tub.”source ↗
“I have scrubbed this as hard as I possibly can with a rag and some scrubbing bubbles foamer and it won't come up so that's why my belief was it was something else.”source ↗
“I just bought a house and the bottom of the shower stall looks like this. All four corners and the edges are coated in this stuff that is hard like concrete.”source ↗
“The second picture is after letting laying a paper towel on it with CLR soaked in for almost 24 hours, and then chipping it off with a plastic scraper. But it would take weeks to do that allll around the edges.”source ↗
“what’s the best way and products to remove a lot of accumulated soap scum, without damaging grout and silicone joints, please?”source ↗
“There's this rubber ring around the bathroom sink that constantly seeps this orange gunk (I assume some type of mold) and leaves leaking splotches on the counter when it gets wet.”source ↗
“Is there any product I can use to help control this better, or is this a "live with it unless you want to call the landlord to replace something" situation?”source ↗
“This caulking keeps peeling after a few months. Any suggestions?”source ↗
“it looks like there are still areas of black along the crease where the tile meets the tub. Should I continue with more concrobium, or is it safe to assume that the mold/mildew is dead and that the little bits of black is more colour than active mold at this point? Should I move ahead and apply caulking?”source ↗
“Attempting to change the caulk on a toliet in a house we moved into a few months ago and ran into this, do I have to remove the toliet to get it all out?”source ↗
“The tile is unfortunately grouted down to the tub. What are the recommended steps here for removing the cracked and moldy grout and re-silicone?”source ↗
Where this came up
People with this problem also raised
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