Coffee is supposed to be an excellent deterrant and if you use it as a spray it will kill them.
Has to be ground coffee- not instant so if you have a coffee plunger or machine, use the leftover coffee granules and strain them. Use the liquid in a spray bottle (cool of course

) and spray on slugs and snails and watch them die. Apparently the caffeine in the coffee attacks their nervous system (so the stronger the better). I've used it on some massive leopard slugs and they were dead the next day. Its a fantastic natural spray and high in nitrogen so most plants will like it. (esp camellias and azaleas)
Then with any leftover coffee grounds you can use them in a thin layer (about 1cm thick by a few cm wide) and make a ring around the plants you'd like to protect. Same again, it's a deterrant and if they crawl over the coffee grounds they will die.
Let us know how you go if you try it.
Chipper5
Apparently coffee grounds are a great soil conditioner too, so add to your compost, as a layer around vegies/garden plants or in a worm farm if you have one
