I have a set of two wooden steps resting on concrete outside a door. The
structure is completely enclosed, but with lots of cracks where hornets can
get in and out.

I am afraid to try to remove any of the boards to gain access because they
are very aggressive.

In a previous post I was asked for pictures. You can see them at:
http://j7000.com/stairs/stairs.pdf

Any suggestions will be appreciated. Thanks.