It's also capable of working on tiles, toilets, and shower doors that have been damaged by hard water.Promising review: I live full-time in a luxury RV. The toilet stopped working after two to three years. It was not obvious, but I suspected it to be hard water scaling. It looked like the porcelain bowl had suffered a loss of its finish. An RV toilet uses very little water. Anyone who has used one knows this. If the sides become 'chalky', it can stick and even stain. It's disgusting. I took out all the water and then slathered it on. It sat for around 20 minutes. I then added one cup of water and used my preferred tool of destruction...a glass scrub brush. There was no need to buff with anything. It was so much better! It feels like my toilet is new. The porcelain bowl as well as vinyl seal flap are both excellent! It is so smooth, that you can't even use toilet paper to adhere to it. It's definitely impressive! It seems to have done no harm to the vinyl flap or rubber seals. ROBYNAmazon has it for just $19.77
