Try Snowbowl....
If that does not cut it muriatic acid...
Try a small area first on the bottom, just be quick to rinse off with
fresh water, and stay away from any metal...
I have used the muriatic on the "Bones" with the Fighting Lady Yellow Awlgrip with good results !
When you go to buy it just do not be buying batteries at the same time...
They will think you are making meth !
