Try "Break Parts Cleaner"...they have Chlorinated and non versions...comes in a spray can...I find the chlorinated version works surprisingly well on adhesive but not a huge amount of experience overall as I only borrow it from mechanics when I run out of my normal adhesive/oil remover out on the road in their shop...it might get at your marker tho...
We used Oven Cleaner to get old hand painted lettering/pinstripes off but you really have to glove up, mask off, use targeted application for only short periods of time or it will burn...even done well, it tended to yellow old light colored base paint...leave it on too long and it would eat right through paint...