I use copper tape for pots, sometimes several layers. It does need to be cleaned off periodically (vinegar or lemon works well, followed by rinsing), as does copper foil. This seems to keep those pesky herbivores off my tender lily seedlings, and others when fresh. Dust, salts and oxidation can build up to the point that slugs can cross the tape, so keep it clean. Out in the garden, I use coffee grounds topped with sluggo, and other slug baits of all kinds. They all loose potency with rain, so constant vigilance is required. Ducks also do a good job of eating slugs and snails, if you are into backyard poultry and don't mind losing the occasional plant. I prefer my ducks at a distance, or roasted. Kathleen