Originally from: frances fish
                        
Ordinary salt will kill slugs, it will also kill weeds,even ragwort ! If you pour salt on the plant, it will kill it. It is not toxic to birds or any other wildlife (It has usually been diluted ) It is not used on weeds such as ragwort because it presumably might make it more palatable as most stock seem to like salt. It probably extracts water from the slug and it dehydrates to such an extent that it dies(unlike killing it in beer when I should think it dies happy !) Cheers, Frances