Picture posting is enabled for all :)
I have and they work just as well as grit or anything else. Nothing much stops a determined slug.
Rox, no those aren't lily beetles, They are a very bright red not brown/red. and they move fast. I don't know what you've found in the fire place but if you google pests you might see a pic of one to identify it, or someone here might know a site.good luck with it. let us know when you find out what they are.