If you have slug and snail problems then you need to read this article.
The famous beer trap. Slugs and snails love the yeast in beer. Here is what you do, bury a half filled container with beer in the ground so they can climb into it easily and die. The alcohol destroys their body tissue. Clean out the container and fill with fresh beer daily. Place these where you are having trouble in your garden or flower bed. It is a challenge to exterminate these pests.
You can create what is called a sugar shack. To do this dissolve a teaspoon of jam, sugar and lemon juice in a glass of water. Pour the mixture into a can with 2 or 3 openings cut in the side. Push the sharp metal edges inside the can. Since slugs love sweets they will climb inside and be killed by the acid from the lemon juice.
Give them grapefruit. Just place your grapefruit rind upside down around your problem area. The acid content will kill the slugs.
If you feel like killing them yourself, then it is time for a nighttime attack. Armed with a flashlight and a salt shaker (sounds scary doesn't it) hunt them down in their favorite feeding place and as soon as you spot one attack it with that salt shaker. A salted snail or slug will not survive.
Another thing to try to keep them off your tender plants is to surround the plants with sandpaper. Their tender bodies will not like the rough surface. Also try surrounding your tender plants with sand several inches deep. They do not like sand and they find it hard to move on, plus it sticks to their insect bodies and will drive them crazy.