I have a bunch of tree stumps that I have acquired. To get rid of them
I've
drilled a bunch of holes into them . What can I put into those holes to
get
them to rot. I don't want to use anything that s poisonous . Thank you
for
your time

If you want this to occur at any time in the near future, you should just
rent a stump grinder and grind them up. Additionally, you can hire someone
with a stump grinder to do it -- most arborists can get you an estimate.
Mushrooms/fungi are a good way to go, but no matter what you do you'll end
up with a lengthy process. Much easier to grind 'em into shavings/mulch and
till it under (or spread it into a new bed).

James