Many of our perennials came in small pots from the coast, and unbeknownst to me, would have snail eggs in them. Eventually they became a problem in our shady acre and a half Robson garden.
I kept an electric kettle in our summer kitchen, would gather 50 to 100 snails in a bucket, and after imagining them going to a happier afterlife, I would pour about half a quart of boiling water over them. To me, this extremely swift ending of their lives, was far better than the other methods where they they might linger in pain. Within a second or two, it was over. After the water cooled, I would dump them at the base of some shrubs or trees in the woodland area.
After a rain, or a good sprinkler session, they would be easier to find. I would even pluck them off of smooth barked trees like the Douglas maples or Saskatoons.
Good luck to you,
@Happy_in_dirt