QUOTE(Bish @ Oct 15 2006, 04:32 PM) [snapback]720000[/snapback]
Fungus gnats are harmless.
Fungas gnats lay thier eggs in the soil which turn into maggots which eat the roots and can cause disease etc. I lost a few plants once because of them. Look in the compost/media for little maggots, a couple of mils long with translucant bodies and black heads. Luckily they are easy to kill off but spider mites on plants in bud is a different matter.
EDIT:
Household items?? You could try a hoover but that's about it I think.