Removing Caulking From Bathtub

I've got a bathtub that I suspect was caulked with a silicone caulk by the builder. What is the best product to use to completely remove the silicone residue? We've used denatured alcohol (not sure this helped) and a product called Lift-Off, which seemed to help, but really didn't get me all the way there. The caulk around the seams of your bath tub or shower serves a very important purpose. While it provides a decorative transition between surfaces, more importantly, it keeps the bathing area If the caulk around your tub or shower has come loose or is discolored

How To Recaulk A Bathtub, Step By Step The Diy Playbook