Don, when I had my tool truck I sold a bunch of the eraser wheels. One of my stops did commercial raps and I had some large decals that needed to replaced, the guy walked up to my 150,000.00 + new truck with a freaking blow torch. He rand it over the decals fast a couple times and peeled them all off in one big piece. So donāt be scared to use a little heat, it works also. WD40 is awesome at getting glue residue off. 3m make a product that you spray on and it takes the vinyl off great but doesnāt get all the glue off. Use the WD40 at that point to get the glue off.
You may have to try a combination of all of the above to get everything off.