Andy writes:

I am trying to stop red jackets from habituating my gas grill.

Then stop buying red jackets and putting them there. Perhaps you mean
"yellow jackets"?

I don't want to use poisons.

I have sprayed them with a soap solution, but they keep coming back
and building nests.

You have a pile of jackets on your grill and they are building nests?
The soap was to clean the jackets? If there are actually bees in your
grill were you trying to clean them?

Anything I can put in there that they won't like being around?

Turn on the grill. Even if you have a pile of red jackets on the grill
they'll burn up. If they are actually wasps or some other kind of bee,
they don't like flames and one fully heated grill will do them in.

--
Dan Espen