Bag/container traps: Ideal for outside use, these sorts of traps tend to be stuffed with a mix of water and an attractant that attracts flies into compact holes. Mild traps: Lured in by a UV mild, flies are captured inside the trap by a glue board or tiny vacuum fan. https://flytraps10484.theideasblog.com/31905485/a-secret-weapon-for-flytrap