I have a cast iron tub in the grandmother swete of my house that I
rent. The last tennent apparently did not clean it for 4 years and it
has a solid over lay of brown crud on it. The tub is nearing the end
of its useful service due to worn porcelein. I do not want to tear it
the tile etc out yet. What is the best way/chemicals to use to clean
it.
Thanks
Stan