Been using this for a long long time...........................

[BUCKY]

Near as I can figure the discoloration is caused by the heat generated by the wheel. This happens very often on white and other light colors. We do not use a Zapper on white at all
anymore. We do it the hard way to avoid damaging the paint. Had a customer once who did not listen to us. He decided to take the Zapper to the lettering on a 2 year old
389 Cream colored Peterbilt, (on the bunk roof cap where a "pet truck name" was). Destroyed the paint! The fiberglass does not dissipate the heat at all so it was really bad.
They took it to a Body Shop and they had no magic solution other than to repaint it.
I once had this discussion on another forum about this issue. A guy claimed he had a "magic solution" he sprayed on for lubrication when removing graphics
which would prevent the yellowing on any surface. When questioned he was not willing to share this information and I do not know how much credibility he really had in the business.

 

[Baz]

I've had that happen before. And it was only with red vinyl. Kinda leaves a stain. I try top avoid erasers when removing vinyl.
Pretty munch the only time i will use them is if i am removing old vinyl that has a million cracks in it.

I've used a 3M product before. Don't remember the name but it was a foamy spray that you let sit a couple of minutes on vinyl and then it just flakes off in a wet mess.
I had used it to remove reflective vinyl and it worked great.