here is a bit, I copied and pasted it, but I have seen more than this maybe it's not their webbi :?
Slugs are a nuisance but most commercial slug killers contain the very poisonous metaldehyde. This kills off beneficial soil animals as well as slugs, is dangerous to pets, hedgehogs etc and the poisoned bodies of the slugs may get eaten by birds who are poisoned in turn. If you don't want to kill slugs, you can protect susceptible plants with a physical barrier like soot, sharp gravel or sand (slugs don't like irritants on their delicate undersurfaces!). If you are lucky, this sometimes works. Or you can trap slugs alive by putting out half orange skins, or sinking pots into the soil with some bait inside, then physically take them away from your garden. Gardening Which, in one of its trials, found that the beer trap, so beloved of organic gardeners, actually killed more beneficial creatures than slugs! So they advised you to drink all your beer and cut 4 inch deep rings from the plastic bottles to make slug barriers for individual plants.
These need to be buried at least 1 cm deep in the soil, but proved very effective at keeping slugs out until the plants have grown enough to be able to withstand a little slug damage. By the way, it is the little grey and white slugs that damage plants, the big black and brown ones are useful scavengers
