Coat it really good with Airplane stripper or a good paint stripper and it will soften it up somewhat,you may have to repeat the process a few times to get it ll off.I will tell you it is a pain in the AZZ to remove! Even a commercial sandblaster has a heck of a time getting it off! It will do it but it takes time.I found the stripper works pretty well.I used 3 coats and then pressure washed it real good then had it blasted and it looked NEW AGAIN!