Diatomaceous earth works very well - in Australia you can buy it from garden centres in boxes but I can't remember what the trade name is. It's a deterrent rather than a killer. I don't like the poisons as I'm sure they kill the lizards. Also I have 2 omnivorous and greedy dogs. I also go into the garden at night with a torch and squash the slugs and snails round their favourite plants. Very satisfying. Liz