True....true,Joe. That's why I like the Toro see-thru....it's obvious if particulates break thru or rusty discoloration gets onto it.
I once took the petcock out of my 40,000 mile Sebring, and the screen's top had either eaten away, or someone had put a hole in it, rendering the screen almost worthless,like Paul brought out. What I've found,too,like you say, maintenance is involved in that petcock screen filter every coupla' years or so. What HAPPENS is that the bottom of the screen will clog,ruining your RESERVE capacity flow when you need it.
Nothing gets thru paper..... Nothing that will clog a jet,anyway. LOL! don-ohio (:^D