After trying all sorts of stuff to remove the 40 year old waterspots on the back window, and reading the recent thread in the tech section here:
https://www.yenko.net/ubbthreads/ubbt...594#Post462594
I decided to try the SPOT-X water stain remover. I found it on Amazon.com for about $15.
Here's the acid rain waterspots that up til were impervious to everything I tried: clay, rubbing compound, 0000 steel wool, 80 grit on a DA sander...
