I did something similar on the collector for my media blast cabinet.
It has a device to rattle the housing and supposedly knock debris from the filter, with a small trap at the bottom to dump the fine collections from.
I had noticed the collector seemed to be louder, and the cabinet didn't seem to be clearing as well, with some media spilling out of the top seal. I just wrote it off to a bad seal...
I was on a dumping spree last week, hit the shop vac, dust collector, and then looked at the cabinet collector and thought "I should dump that".
The filter was COMPLETELY packed with fine dust, and was HEAVY.
Took me some time to get it cleaned out, and a huge dust cloud outside.
Amazingly the tank clears now, I can see what I am blasting, and the motor is much quieter...