BB4A wrote:
A photographer I mentor recently had the same thing happen. I advised placing an electrical cable tie around the outside of the filter frame, pulling it tight, and then using the tag end to unthread it. The cable tie applies pressure evenly around the bent filter frame, pressing back in where it’s bulging out of the lens thread and thus freeing up the area where it’s bulging into the lens thread.
Worked like a charm, first time.
Just like a strap wrench.