Copper has been used as an effective snail and slug barrier for years because the metal reacts with the mollusks' secretions, causing a flow of electricity.
Even thin strips of copper will conduct enough electricity to "bite" a snail or a slug.
Will not rust, stain or contaminate, turns a beautiful verdigris color with time.
Place copper strip around pots, trees etc. or place in rodent holes as a deterrent.