Find a container about 1 to 2 feet in depth with a diameter of about 5 inches. This will act as the beer trap container for the snails.
Dig a hole in the ground that has the dimensions of your container. Make the hole slightly bigger than the container so that you can easily fit it inside.
Place the container inside the hole in the ground and fill the gaps between the ground and the container with earth so that the container is sturdily set in place. Make sure that the rim of the container is level with the ground so that the snails can easily access it.
Pour beer into the container. The smell of the beer will attract the snails and they will fall into the trap and drown. For extra effectiveness, you may also choose to add a small amount of honey to the beer mixture as snails are highly attracted to the smell of yeast and honey. Otherwise, you could use a honey-flavored beer.