The excluder works due to the queen being larger than a normal worker bee and cannot pass through the slots. The rounded surfaces allow workers to pass readily without damaging their wings.
It is normally only used during the honey season (spring/summer) and should be removed during the autumn and winter months so the bees are able to group together to keep warm.
Stainless steel excluders are highly resistant to corrosion. They can be steam cleaned or boiled.
Best avoid galvanised steel excluders as honey is acidic and corrodes galvanised (zinc) surfaces. The corrosion products will contaminate your honey.
Best avoid punch-plate excluders as the aperture edges are sharp and damage bees' wings.
