salt, crushed shells, coffe grounds all that stuff is ineffective - best way to get rid of slugs night time slug hunt with torch then cut in half with a swif chop of a trowl and leave for the birds (they are normally gone by morning. Or, put out takeaway trays sunk into the ground so lip is at ground level and fill with beer or cider. the slugs cant risist the smaell and drown. Personally the I find the first less traumatic as emptying the trays is gisgusting.