So last night I made the ultimate dust collector mistake and let mine get full. It filled up the filter. I have a Mini Gorilla with a small canister filter. What's the best way to get these clean and how can I tell if it is clean? I shook it, banged on it and blew it out with an air hose but it still appears to have quite a bit of dust on it. Is it just a matter of time doing those three things to get it clean?