I would just like to report that I have had enormous success killing slugs with beer in SW Ohio. Stroh's and plastic cups are all that are required. I caught seven - yes seven - slugs in one night with day-old beer. Dumping seven soggy dead slugs from a plastic cup was both nausiating and rewarding. I think so far I've killed about two dozen 3-4" adult slugs this year, mostly with beer but also by smashing those that I happen to see when I'm out at dusk or dawn. Plus I've probably killed about half a dozen baby slugs when they've been tracked into my house by the dog and cat. If it weren't for the babies getting into the house, I probably wouldn't be half as determined to kill the breeders.
But I am wondering (since I was asked) if slugs serve any purpose in a garden. I've only seem them eating my flowering plants, which signed their death warrants.