Hmmm... I'm into researching slugs right now because they have wrought so much havoc with my hosta petioles this year, instead of mere leaf damage. I found this elsewhere on GardenWeb.

• * Posted by kimmsr 4a/5b-MI on Fri, Jul 24, 09 at 7:46

I keep seeing references to using coffee grounds as a deterrent for slugs and I keep seeing slugs crawling over coffee grounds with impunity. Dry, moist, new, old, used, unused coffee grounds, in my observations, have done nothing to slow, much less stop the slugs.

What I have seen is that cold, caffeinated coffee sprayed on plant leaves has reduced slug damage in my gardens for years, even though many people here tell me that that will not work even though research done by the USDA in Hawaii has shown that it does work. Some people insist that the slugs in Hawaii are a lot different than the slugs on the mainland and therefore this cold, caffeinated coffee will not work.

Here is a link that might be useful: Gardenweb Thread About Snakes, Slugs, Coffee