Well constructed 2 1/4" deep wooden frame with heavy flannel-coated chemical absorbing canvas liner. Heat from Sun on metal cover evaporates chemical and forces bees out of honey supers
Tip: Apply a small amount of Fischer's bee repellent/Bee Go/Honey Robber to the felt inner cover of the fume board in the shape of an "X" or "S". Place fume board on the top of the upper super with corners of frames exposed for airflow.
Removal time will depend on temperature and humidity.