Well all you can do realy is wash and change b4 going into your grow room if you have been in the garden or a friends grow room b4 hand.
But they will somtimes come in through ventelation .
They are bastards ,once they r in they r in and i found nothing to cure an infested grow room, not even predators.

I spray vehicles for a living , so when my grow room is empty i fill my spray gun with bleach and water 50/50 and spray every square inch including lights and balasts which is very sucsesfull .