wrote:
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.

Looks like enough openings to hit with the canned wasp spray. Just
squirt in. It will knock down any hornets exposed immediately with
little danger to you. If you can find nest opening, one shot may be
enough to do them all in.