Just keep them until they are a half decent size then sell them off to other members. I raise ramshorns in all my shrimp tanks (sell them at auctions) the shrimps don't care, and the snails eat any leftovers, so its a good trade.
Pond snails I would pick off and keep in one tank (no filter just some plants for them to snack on) and when they grew a bit I would squish them and feed them to my CPOs....great for growing those babies fast as the meat from the snails is high protein.
Always a way to make something off these snails...no need to kill then just re-organize your thinking and find a use for them.
