Weak Ejectors - Cleaning advice?

[TNR]

I have a VHE 20ga - all I've shot out of it are RST 2 3/4 shells. The gun and ejectors function flawlessly but after 5 or 6 shots the right ejector gets progressively weaker until it barely pops the shell out.

I assumed this is due to it being dirty but I have been cleaning that extractor with hoppes on a q-tip, etc and it will eject shells very strongly. But, again, after a few shots it will do the same thing - work really well for a round or two and then, again, progressively weaker.

Any advice on cleaning it? Or is there possibly something else going on?