yeah, makes sense eileen. once you get that 'debris' stuff out most pumps shouldn't have much of a problem with the regular denitrus build-up (unless you continually have debris 'created' in your sump).
the 'gravel vacs' should work fine too, except they use gravity siphoning normally, and since most people keep their sumps on the floor (except for mike ;D) it would be tough to get a good siphon going.
wet/drys aren't that expensive if i remember correctly, i got mine used for around $20-30 but even at HD the bare bones versions weren't too bad (unless you want the big, big commercial versions).