Beer traps work. But because of the yeast smell, not the alcohol. Yeasty
sourdough starter painted on some rotting
wood works almost as well.
Chicory is also a slug magnet, yet the plant shows few ill effects. In the mornings, I pull a few chicory leaves, complete with resident slugs and throw them in the
chicken pen.
Halved citrus shells also work. A grapefruit half (minus the part you had for breakfast) can easily pull in a dozen slugs.