Depends on how it got there.
If you changed the ff, the not yet filtered fuel on the outside of the ff mixed with the filtered fuel on the inside of the ff.
My experience has been that when I take the ff out, the unfiltered mixes with the filtered as well as any crud on the outside of the ff can wash off in the removal process and is now in the soup as well.
I get the ff canister totally clean / dry it out / blow it out with an air gun / inspect to be sure no trash is anywhere in the canister / blow off the new ff to be sure nothing is hanging on it / asceptically as possible reinstall the ff and start the ff top on (2002) / get the top snug / loosen the fuel fitting just before the VP / bump the starter (fuel will squirt out the loosened fitting) / tighten the fitting while the lp is still pumping.
Result is no air and she cranks right up
Bob Weis