Originally Posted by NCWC

They are shaped like a funnel and are made from thick paper. The mesh is super fine for filtering paint as you pour it into the spray gun. I used them quite a few times to filter dirty fuel when I raced moto-x. Try to find an empty fuel jug to put your cleaned fuel in, you wont get all the dirt out of the old jug but you can get it out of the fuel with those filters.