You may have read that you can deter slugs by surrounding your plants with copper pennies. Don’t waste your money. The amount of copper in a US penny is a just a thin coating over a zinc blank. And there is no evidence they “give slugs a shock.” How would that happen?
A thin band of copper might deter slugs because of the sharp edges, though, not because it’s copper.
The best non chemical approach is surrounding your precious plants with diatomaceous earth, which is like little bits of glass to the slugs. Unfortunately it’s expensive. And the best chemical slug bait is metaldehyde, but it is poisonous to pets, too, so you have to apply it with that in mind.
We haven’t seen that many slugs this dry summer, but we found one yesterday munching on the remains of our broccoli. We scooped him up and put him in a container with 3 pennies, one partly under his front feet. He wasn’t shocked, but he slowly turned around to go another direction. It looked more like he didn’t want to climb the lip of the penny than it was in any way unpleasant to him.
Call this experimentally uncertain at best. The other remedies work better.
But stay away from beer traps: they actually draw slugs to your garden.