How about a Slimy Solution ... have you tried predator decollate
snails?

In our organic vegetable gardening classes, I often tell about my five-
pronged approach to snails, and the use of predator snails is one part
of that broader solution.
I described my organic snail and slug solutions online here
http://legacyla.net/transformation/?p=271

International Garden Center in El Segundo has agreed to place an order
for decollate snails for us. The pointy decollate snails eat the pesky
round brown snails.  Keep in mind that brown round snails are an
invasive exotic species and we simply don't have any natural predators
to keep them in check.  The carnivorous decollates are easy to
introduce into your garden ecosystem.
See a photo of decollate snails http://www.growquest.com/snail_2.jpg

If you would like to bring predator snails into your garden, you can
join in on this group purchase in one of two ways:

1) stop in to International Garden Center, tell them you're from
Environmental Change-Makers, and buy your snails directly.  Snails
will arrive this weekend.  International Garden Center is at 155 North
Sepulveda Boulevard, El Segundo.

2) let me know via email how many containers of snails you want, and
then meet me at the Community Garden at Holy Nativity this Sunday,
April 10 between 12 noon and 3pm (I'll be staffing a table at the
garden tour).  I'll have your snails and you can reimburse me.  Note:
I cannot hold snails beyond Sunday, so if you can't meet up during
these hours, please use alternative #1.

The decollate snails run $18.99 per container, and one container is
enough for an average city lot.

Joanne P