Sue, when I mentioned plastic bags, they were behind a car mirror.
I did not want to use pesticides.
So I totally enclosed the car mirror with bags and taped them shut.

The yellow jackets poked holes through several thicknesses to get in /out.
So I totally covered the bags with duct tape. They coudn't punch holes through
that.
Left it there for 3 weeks/a month, so they were cut off water/food and
"fried/dried" in the hot sun.
Then I removed the crumbly nest and remains of YJ's

In your situation, I don't think plastic will work.  The cooking oil will drain
down below and the yellow jackets outside will continue to come in..new females
will start if the Queen died from hot cooking oil..is my thinking on that.
Any YJ down there will be able to push their way back up beside the plastic or
through it..
They're determined little " beggers" and nasty too when getting anywhere near the
nest.
J

No it didn't do that. It was walking upwards, which is what they do when
they can't fly, it didn't want to be there at all. When your shirt moved
against it it felt threatened so used its sting as a defence.

Mary

I'm generally a live-and-let-live kinda guy - you can ask the mole who
occupied my back yard for three years or so.  I think he died of old
age.

I had a nest of ground bees in my front yard this summer - a hole in
the ground about the size of a penny.  My wife told me to watch out
for bees as she'd seen the nest earlier.  I'd mowed the front yard a
couple of times without incident so I wasn't all that worried.  To
make a really long story short I mowed the lawn in late summer and
somehow offended the bees - as I now had a bee fountain in the front
yard.  I even let them have the lawn mower  :)

Anyway, I waited an hour or so for the bees to calm down and tried to
finish mowing the front lawn but the bees would have no part of the
idea.  Normally it wouldn't bother me because I don't like mowing the
lawn but this particular bee nest was about a foot from our front walk
and the bees were angry.

So - I went to the hardware store and ask the lady what I can do about
bees.  She says it's been a bad year for bees and points at some
aerosol wasp and hornet spray...

...that turned out to be completely worthless except that it was great
fun shooting the bees out of the air with the spray can and that
because the wasp spray had a petroleum base and I expended a couple
cans of it on the bees and their nest I managed to kill a patch of
grass around the bees' nest.  Didn't really affect the number of bees
but did really piss them off.

So I got on the Internet and started reading.  Found out that Sevin
dust (made by Ortho) is lethal to bees but relatively safe to handle.
Up until a couple years ago it was approved for dusting pet beds to
get rid of fleas and suck.  You can still use it on pets but not on
kittens or puppies.  Sounds reasonably safe.

So I went to another hardware store and bought a 1 lb can of Sevin and
the man behind the counter said it was the wrong time of year to be
dusting roses but he'd be happy to sell me the Sevin anyway.  I told
him that I wasn't dusting roses and explained about the bee fountain
in my front yard.  His response was that if I wanted to use Sevin it
would be effective but would probably kill every bee in the yard.  I
guess they carry it into the nest and it kills everybody in there.

I bought the stuff and used about an ounce in and around the hole.
Two days later the bees were gone and have not returned.

Apologies to beekeeper Mary as like I said, I'm generally a
live-and-let-live kinda guy.  But if one wants to get rid of bees the
method I mentioned is highly recommended.