Gophers are herbivores (roots and bulbs, sometime pull down greens), moles eat insects, grubs and worms. A tiny dab of peanut butter works great for gopher bait (at least the western pocket gophers), so, yeah, not sure how to bait moles, maybe part of a worm? Even without bait the movement through the tunnel is what you are using to snag them, especially with the wire traps like those from Trapline. Place them underground in the tunnel or in the soil near the entrance/exit.