What’s a good way to clean a porcelain sink that has picked up what I can only guess are mineral deposits from the water?
Good ol’ Comet and Ajax aren’t mustering to the task. They’ll clean the surface crud, but even though porcelain is described as non-porous, I’m starting to think this stuff has established roots, so to speak. I’ve tried letting the aforementioned cleaners sit, wettened, for hours in attempt to bleach the sink. No luck.
There are various toilet cleaners that claim to get rid of mineral deposits, but they all (that I’ve found) warn against using them on anything but a toilet.
Maybe it’s not really a porcelain sink. What else might a rock hard white kitchen sink be made of?
Now I’d previously discovered that when I do a large load of dishes (18 and a half years without a dishwasher - maybe I just need to move) and am stuck with a large accumulation of soap bubbles that won’t easily go away, a fine mist of charcoal starter and a match will - POOF! - make that problem disappear.
But I doubt that’s the source of the problem, as I’d expect that to leave, if anything, carbon residue (it apparently leaves no residue besides a soggy match). My problem is mainly a ring of brownish stuff about 2-3" up on the walls of the sink that is impervious to the cleaners I’ve tried.
If the stuff is really mineral deposits from hard water, bleach won’t touch it. Fill the sink with hot water, and throw in a cup of vinegar, or better yet, citric acid. Let it soak. That should dissolve any carbonates without hurting your porcelain. If in doubt about what’s in your local water, ask your geologist friend.
If your sink is really porcelain, it’s the same thing as your toilet. There are porcelain-clad cast iron sinks, and you can tell from underneath. Really fierce acid cleaners will begin to eat the porcelain after they finish with the lime deposits. Scouring powders will scratch the finish, and new deposits will glom onto the scratches. Scotchbrite (polyester scrub pads) will also scratch porcelain, and glass, too.
If you use heavy duty acid cleaners, rinse thouroghly afterward. Use the gentlest acid possible.
Vinegar might work but may need a long time to soften deposits. I might use Lime Away or “ice machine cleaner”. They use it here to clean the crud out of ice machines. That stuff is real strong and can only be purchased at appliance parts stores. Also, after years of cleaning with Ajax or Comet it is likely that the protective gloss is gone from your sink and the porcelain truly is pourous. It will ruin sinks,toilets and tubs over time.