Check out this solution using beer from @Linda Meyer-Kelly: http://www.hometalk.com/2151898/slug-saloon
I saw this same question on another site, just today! One of the commenters suggested using used coffee grounds. They are acidic, and the slugs don't crawl over them!
I have used beer in a container that both slugs and snails can crawl into. It works as they are attracted to it. Also have heard of coffee grounds, also crushed egg shells around plants -needs an awful lot of eggshell though! There is also a product - copper tape - you can buy from nurseries, garden centres and some hardware stores. Put this as edging around your raised garden beds and pots to keep slugs and snails off. They don't like crossing it apparently. Not tried it myself though. The other way to go is to take a torch and stroll round the garden as it is getting dark out (especially after rain) and simply pull them off your plants and get rid of them - I leave it up to you how you dispose of them - LOL! Please don't pour salt on them as that is a very cruel and painful death - treading on them would be more merciful than that.
Diatomaceous earth is organic & found in many garden centers. Sprinkle around your plants or all over your garden/flower beds. It's very abrasive to slugs and is also good for controlling ants, roaches and other pests around your home & yard.