I've never had this problem before but after getting a new toilet installed, the caulking this plumber used has become stained with urine. I have used bleach, all sorts of bathroom cleaners, scouring powder, the scrubbing sponges like Mr. Clean's, etc. but NOTHING REMOVES the stain! I know it is "clean" after using so many products but it is extremely unsightly! Is there an effective cleanser or another caulking I can use that will be less likely to stain? My husband takes a medication that is coated with a yellow covering and it may be that BUT didn't have the problem with the old commode! Thank you!