When it comes to that crisis you-or-them situation you just have to do something. Slug-pubs actually attract more slugs to your garden. A few years ago slug killers based on aluminium sulphate were approved by the organic fraternity but the approval has been withdrawn. The little pellets of aluminium sulphate are extremely effective, they don't harm any other wildlife and they dissolve away to nothing. You can even dissolve them and water them in (five dessertspoonfuls to a two-gallon watering can) if you have a severe infestation. There are also pellets based on ferric sulphate that are supposedly "organic," and they work very well and last longer, though thay have a tendency to go mouldy.   I really don't see too much wrong with just ordinary meta pellets, though they are severely disapproved of in organic circles.   By the way, the big ugly slugs do very little harm. It's the nasty little keeled slugs that often secrete themselves in the soil that are the real menace.