On Jun 25, 4:10*pm, windcrest wrote:
On Jun 24, 10:46*pm, wrote:

I have a set of three 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. *I can stick
a tube into the interior through a crack

At night, I tried pouring a small amount (all I happened to have) of
ammonia through the tube into the interior yo see if the fumes would kill
them or drive them out. *It didn't happen.

Any suggestions will be appreciated. *Thanks.

Seal up the whole stairway airtight with plastic sheeting. *Now get
about 5 or 6 aerosol "bug bomb" cans and gas them to death under the
plastic by releasing the bug bombs under the sealed plastic. *Leave
the plastic in place for a few days so they are entrapped within the
poison. *Nothing will live through that. *Make sure the plastic
entirely seals the stairs by duct taping it to the house and slab,
etc. *Additionally you can pump hornet liguid with an atomizer (a
paint sprayer) under the plastic, they gotta breath and eat all that
poison some time.

Use clear plastic that lets in light so they have a desire to exit
their nest into the poison vapors.