Robert Macy wrote:
On May 26, 4:08 pm, " wrote:
My bathtub has a stain in it that is impossible to remove so far.
Here
is a picture of
it:http://www.flickr.com/photos/5423000...7629878927850/.

What should I use to remove the stain? I tried bleach and it does not
work. It feels rather rough and even powderly at the stained area.

Thanks

Whink, mild HF acid


HF? OMG! NEVER!

Even the tiniest amount of the most diluted Hydrofluoric acid is a calcium
blocker and will stop your heart. The treatment for HF poisoning is
hit-and-miss.

I think you meant HCl or hydrochloric acid, sometimes called Muriatic acid.
Be prepared for fumes and set up some good ventilation.