Just reading through the fuel filter thread and a thought came to mind. We filter our fuel before the tank, after the tank and sometimes we filter the air going into the engine but one thing we seem to neglect (at least as far as I've observed) is the tank vent air. Our tanks suck in anything that's in the air, dust, lint, pollen, feather down, etc etc. Anyone else ever considered this? Thinking about it, it seems to become clear too me that despite my efforts to keep the fuel supply clean, I invariably end up at some point having to remove the needle and removing some chunk of swarf and wondering where the heck it came from. It must be coming from the vent air and it has only one way out, right through the NV. I think I am going to start filtering the vent air.