You will find next to nothing in the pump pick up screen. The screens are far more coarse than the fuel filter element.
I am a firm believer now that you really need to change the fuel filter every 30k miles as the paper element is rather fine and picks up all sorts of crap.
If you bother to cut open a fuel filter, you will likely find the inside element caked in a black sludge. Depending on how dry the filter is, the black will be an ultra fine powder that you can scrape off.
You will be surprised how thick this black gunk will actually get.