I have a few sets of 69's but they went through my garage fire and are coated in rubber from burning tires. I have not found anything yet that can remove that crap. I even tried adhesive remover and a 3M stripe off wheel and it doesn't do much. I am surprised there is not some kind of chemical that can remove that stuff easily...
The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it.
