Rear Window Defrost Element - Corrosion
 

You can feel bumps on the copper elements. Any ideas on how to clean it up? A little sanding perhaps?

I had the rear window tinted and the film "bubbles" around the element.

I use #0000 steel wool on it then clean it off nicely with windex or such. The window tint didn't bubble because of the corrosion, it more than likely bubbled because they didn't clean it properly. The surface has to be completely oil free for it to adhere well enough. Since soot is exactly the opposite if they didn't clean that area very well then.... I actually heard of the steel wool cleaning from professional window tinters. While I can do any semi flat side window I still haven't perfected rear windows. I don't have the patience I guess.