The beer works-but as you said it cannot be too high off the ground. Another slug catcher is supposed to be ground coffee.
So far not much luck.
I live in Sarasota, FL. I read that butterflies like beer though they drink it through their feet. I put it out in saucers with pebbles. The results make me think that possums or racoons are drinking the beer cuz the pebbles are always pushed out of the saucer. Maybe I’ll put some Miller Lite in the saucers; even a possum wouldn’t like that crap, would it?
We used to throw old coffee grounds down in the ditch when it rained. The earthworms would head straight for it and we snatch them all up and go fishing.