We have a plague of flies- small ones but constantly hovering. The lid has broken off my neighbours wheelybin and they're waiting for a replacement- maggots and flies were in bin but bleached and scrubbed now- they will be back though. Wheely bin lid should hopefully be here in next few days. How can I keep the filthy flies away in the mean time? It's doing my head in. We don't leave uncovered food/pet food out but do need to sometimes have windows open. Help, they're driving me bonkers