I have very heavy hard water scale on my fiberglass bathtub. Muriatic acid has cleaned my toilets nicely, but I don't know if it is safe for the fiberglass bathtub. I have tried every other cleaner like bleach, CLR, comet, etc....
Vicki from Round Rock, TX
I have recently been using the Mr.Clean Magic Eraser in the shower and glass doors.
It is amazing how well it works with a little elbow grease.
CLR is a strong acid, although I do not know if it is as strong as Muratic acid. However, if the CLR did not clean out the scale, I don't think that Muratic acid will either. But if it didn't harm the tub, I think you are okay to try the Muratic acid. They are both very strong acids. Perhaps you just need to leave the CLR on for a longer time.
Try bathroom cleaner plus from Amway works great
On a previous post about fiberglass bathtubs someone said that "The Works" available in Dollar Stores of all places was great on fiberglass. Well I went out and bought it and love it. It has the consistency of water, and since my tub walls are fiberglass too, one bottle only lasts me two cleanings. For $1 it's certainly worth trying.
Soak a paper towel in white vinegar, place on the affected area and let stand for an hour or more, rinse with clear water. repeat as necessary
Sounds to me like someone has cleaned it with the wrong chemical before and etched the finish so that it stains more easily than ever. Remember to apply a protective coating should you get it cleaned, so that you won't create still another problem. God bless and help you. : )
I have the same problem and the only thing that works is TIME W/MR. CLEAN MAGIC ERASER. LOT'S of time. Also better to keep up w/it every few days so it doesn't build up. Better yet leave it in the shower and have the family take turns cleaning after each use! God Bless<><
After you get the fiberglass clean, there is a product called Gel Gloss you might try. It cleans and coats the surface with a durable finish, and it's easier to clean. It works well on pressed plastic sort of surrounds and tubs, just a lot of elbow grease to get the surface clean first!