You could also close the suitcase so they couldn't get out, and then you'd have a lifetime supply of dead flies.

Speaking of dead flies, I notice Shane hasn't been around lately.

Did you hear the story about the farmer who wouldn't put up window screens? The local agricultural agent told him that it would be healthier, that it would keep out the flies that also infested the outhouse. The farmer said, no, he'd just toss some lime down the outhouse and that was lots cheaper than screens.

So a few weeks later the ag agent comes around again the lo and behold, the house is fully screened! He asked the farmer what convinced him to put up screens, and the farmer replied, "Well, I noticed that the flies were leaving little white footprints in my food."