Not wanting to waste beer, I used some old sourdough starter instead. I mixed some of the alcohol with the dough and added a bit water. The mixture went into individual yogurt containers and I dug holes for them in the garden. It certainly attracted and drowned slugs. When I lifted the containers out of the hole, I found the hole lined with slugs. Out came my salt shaker. :)

I'm going to water down the mixture and see if it still works. The first batch was strong and I don't have that much alcohol.