If they didn't come back, I would happily relocate them to another part of the garden.
Malt vineger (I don't dilute). They are dead in seconds and no fizzing, the vineger preserves them so there are no bad smells and you can use the same pot until it is full, then on to the compost heap.
Lidl sell pint bottles at 17p, so not an expensive exercise.
I only protect the veggies, everything else has to fend for itself. Don't forget to leave the leopard slugs alone, they eat the others. I have one inside the polytunnel on daily patrol, it is now 7" long so must be eating well!