How do I remove a stain from a claw foot tub?

Try Easy Off No Fume oven cleaner in the BLUE can. Works on enamel, porcelain, and fiberglass. Open windows as there are some fumes. Just spray it on, let it liwuefy, rinse well.

I always hate to suggest it but the ONLY thing that would take the calcium deposits off the bottom of my tub (and then rust stains) was The Works toilet bowl cleaner. Someone is gonna reply here and say to never use it because its toxic... And it is. Its really hard core stuff but if you've tried EVERYTHING else sometimes there's just no choice.

IRON OUT ZUD both for rust

Check this product out, developed by a pro

https://www.qvc.com/Don-Asletts-T3-Tub-N-Tile-Foaming-Concentrate-%26-Scrubbing-Brush.product.V35991.html?sc=SRCH

I just read this article, might work on your tub. I may try it for my sink.

https://www.exquisitelyunremarkable.com/2018/04/the-best-way-to-clean-scratched-dishes.html?utm_source=hometalk

Lime away, let sit after rubbing it in. CLR is good too. Bit to get it back to its beauty, Lowes has a kit that you can use to redo it and make it brand new again. Available in the paint dept.

Pumice Stone, I had a ring in my toilet bowl that I just couldn't get rid of no matter what. I've also used the stone on my porcelain tile to get rust mark's off.. I bought mine in grocery dept, cleaning supply section at Walmart.. Cost around $2.00 & i now keep a few extra's on hand....

Like was mention above I use a Pumice stone to clean any porcelain surface, cheap, non-toxic, works great. better than any toxic chemical

Have you tried one of those magic erasers? They really are wonderful. I clean my tubs with them all the time and it makes life so easy. Alternately, we use Dawn professional blue (yes, the dish soap) to clean bathtubs and showers. It totally gets rid of soap scum very easily. I'm not sure about stains.

I’ve had good luck with Zud as well.

Vinegar for rust.. let it soak for a while

Try Magic Eraser first. MIght do the trick. That stain is from water sitting there. If that doesn't work maybe barkeepers friend cleanser.

Try wetting the area and sprinkle powder used to clean dishes in the dishwasher. I used Cascade powder. Use plenty and let sit for several hours. May have to do it more than once.

"The Works" Get the toilet cleaner. Takes care of whole bathroom! Been in nasty well water rentals that were REALLY orange! Takes it off! $Tree and Walmart (by the 8 dollar stuff).

Try either bar keeper or Clorox clean up. Bar keeper had been off my cleaning list until recently and then discovered how much it can clean.