I set 3 sheets on stands among 12 figs in pots of different sizes 2 days ago. While I see gnats flying from time to time around, I don't see them captured :(

I use those yellow traps:
http://www.amazon.com/Yellow-Sticky-Aphids-Fungus-Miners/dp/B005F5JOHA/ref=pd_sim_lg_16

They feel and look fresh. How do I lure the beasts in ???
Any scent would help? 

I haven't had any problems catching them without scent. However, Walmart sells some here that includes scent.

They love, love, love, oyster mushrooms. I have never tried baiting them but that is what I would use. You can eat the rest too.

Hmmm.. oyster mushrooms, would you just sprinkle the yellow strips with tiny particles or set a large piece of it underneath?
I would hate to attract the gnats from all my neighbors, they need them too !

I think small pieces would dry out too quick and not smell as much.

Wet, yes, you gotta love your enemy :(