How do I remove dozens of roaches from a vent from my roof? :eek:

Roaches are on of the hardest pest to get rid of I would advise calling a pest control company to take care of the problem. Good luck.

Since the vents are sealed by the traps in your home I would First have everybody refrain from flushing or draining and take a bug bomb up on the roof and secure i8t with a hooked coat hanger and set it off and lower it down a piece in the vent and then seal off the vent while the bomb did its work.
Good luck, Tom