I used mineral spirits and some thinner when that ran out , lots of elbow grease and you will be black all over from the old sealer , try looping a rag over a dull flat blade screwdriver for in the deep grooves , it took me a couple of hours each night for 2 nights after work but I re -used both mine and the glass guy was impressed enough to offer to pay me to do a pair for his little 66 barracuda but I laughed and declined ,to much work but way better than the repro ones