I just did my EPDM rubber roof and used a puddy knife - the 13 year old caulking came right off where it was loose/dry. I left the firmly attached caulking on and re-caulked right over it. No damage to the EPDM rubber, so I would think if you are careful it would work on paint/gel as well. P.S. I tried Mineral Spirits to loosened up the old caulking a little - it worked a little, but not much. II stopped using it after about 2 seams. What did seem to help was a hot sunny day - 85 degrees+.
Tom and Amy from Northern Virginia.
2000 Allegro 454/Workhorse P32/TST/Crossfire
Life is a DIY project - enjoy it.