Slugs do not like anything rubbing their belly. You can try putting cedar bedding down, like the kind you would use for a hamster cage. That would cut into their belly, and deter them from your plants.
The cheapest, most artificial smelling pancake syrup you can find diluted about 50/50 with water will pull them in more effectively than anything else I know. If you would rather not buy cheap, rank syrup choose some other combination of intense sweet and fruity.
The most effective thing I have found to date for protecting my sunflowers from slugs has been coffee grinds. I simply scatter the grinds on the leaves and around the plant. I understand that placing small containers of ber around is also good.
If you place a shallow bowl full of stale beer near the base of the plant the slugs will crawl in and drown, otherwise a commercial slug killer will work.
