Use a tall drinking glass with a little bit of wine or beer in it instead of vinegar, don't add dish soap, and cover the top with plastic wrap pulled tight with a few fork or toothpick pricks in it. Flies will get in but few will be able to get out. A few will die in the wine/beer, but the vast majority will stay above it. (Heck, the ones in the wine may be the ones that died naturally due to the short life span.) Then you can take it outside and let them go, usually once or twice a day. Also, don't leave the window open; I've found that more get inside than out that way, even if there's better food outside. If you've got fruitflies mating around your sink, other fruitflies will prefer doing that instead of finding food outside; plus the ones you let out could find their way back in.