Recommendations for loosening slip joint exhaust tip?

I recently picked up a used APR exhaust that uses slip joints and clamps to hold everything together. Coming from an exhaust with v-bands, these slip joints are a royal pain in the butt to deal with.

One of the exhaust tips was previously installed and clamped way too far down the pipe and I'm trying to pull it out a bit but it won't budge. I hit it with a healthy dose of PB Blaster to no avail. I think the caked on exhaust soot is getting in the way. Any recommendations on how I can get the exhaust tip to slide out?

Smack it was some type of mallet. Then get an exhaust show to tack it on with a few welds

Wiggling it will also help break (enlarge) the connection of the "crimped" down outer metal

Or maybe a little bit of heat to get the outside metal to expand and slip it off?