If it is very tough stains clean it with a pumice stone, be sure your tub is porcelain or any supermarket bathroom or surface cleaner can work; only the thing is you have to clean it on regular basis
make a call with the experts or just replace the old one. that's it!
cable railing system
you need to go get a PUMICE stone
its the only thing that will clean up old porcelin with out damaging it. believe me
i knoew of what i speak
i have installed 2 or 3 thousand tubs. in new homes
and every once in awhile we get a funked up tub that has been used as a toilet and abused in all sorts of ways you dont even want to know. instead of pulling them out. and occuribg all that cost we use a pumice stone.. just water and rub it. all hard water stains will come off..its not fast. it will take about an hour to clean it up
Try Bar Keepers Friend, even Wal-Mart sells it.
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