My electric dryer is in the basement and is vented outside. The vent is even with my wooden deck and is next to the stationary patio door. About four inches of the wood from my desk is cut away around the vent to accommodate it. The vent has a yellow plastic cover and a round plastic flap covering the hole. In the winter at the end of a drying cycle it freezes to the cover. I tried petroleum jelly on the outside of the flap but it still freezes. I'm not keen on breaking the cover off either, unless that is the only solution.
Answer:
Knocking the flap off will also leave your vent open for company: mice, bees, cats in some cases, skunks, birds, etc. Try taping a small weight to the outside of the flap so its a bit heavier and that should do it. There are also spring arrangements you can attach to these things and that automatically kicks the thing shut when the pressure from the dryer is removed.
