Help with Old Red Devil vac filter

[Jesse Cloud]

I've got an ancient Red Devil canister vac that's used inside the house.  The 'prefilter' is a round shaped bit of woven plastic stuff about 1/4 inch thick.  The wife complains that it is next to impossible to clean anymore.  I checked Red Devil's website and the prefilter is "no longer available".

Has anyone ever fashioned their own replacement filter?  Could I maybe just cut a piece of scotchbrite (similar weave) to fit?

Hope you can help.  I think the wife has her eyes on my CT22  [eek].