Male sativa plants are usually pulled and binned, but they have a few uses beyond pollen. The stems on tall lines are fibrous enough for small craft projects, the leaves can be dried for tea or juiced, and a selected male is worth keeping in isolation if the line is rare. The breeding notes on https://hazesativaseeds.com make the point that identifying a good male by structure and smell of the stem is a skill worth learning before discarding every one. Most still end up composted, which is fine, but the reflex to kill them on sight is not always the best move.