I have been reading and hearing on best ways to get rid of snails.. now I personally dotn like to get rid.. as they feed the blackbirds and thrushes that have now taken residence in my garden.. so what I do and find is hte best way for all.. is..
take large flower water tray.... then find a smaller one by at least half or more in size and a rock. place this smaller one inside the larger one. and put rock in to keep it in place.
place salt in the gully between the two trays. fill it up with a enough to fill it half way at least....place in shaded area.
then go snail hunting. then put all u find in the smaller tray.. and leave for the birds to eat. the snails wont go over the salt.. and even if it rains it stays salty and they wont go thru it. the blackbirds and thrushes come and use the stone to break the shells and eat them. and all are happy.i find the birds also root through my plants looking for more. when tray is empty and they keep them at bay.
with slugs u can do the same thou i leave them in a seperate one.. but the black ones i put back as i believe they are not plant eaters.. if u have frogs or hedghogs they will come get them.