Well after marring the heck out of the endcap and the can, I finally realized how to remove the endcap. The siilcone had made a tight seal and the endcap was almost impossible to remove because there is nothing to pull on. I tried prying between the endcap and can for over 30 minutes and never could get them apart.
I finally used some tiedown material and rigged it up like this. I put the rope around a post and pulled on the can until it popped free. After some sanding, both the can and the endcap edge looks better but not perfect.
Anyway, just in case anyone has the same problem I did, this is what to do to remove the endcap.
