On 07 Sep 2018, Frank "frank wrote in alt.home.repair:

I have friends that do it at their hunting camp and house went
left for a few months in the winter.

Well, maybe I'll save it for that day when I have a hunting camp!

No, seriously, I'm trying to get rid of all the crap I've hoarded,
"just in case..."

Dex Cool is mostly ethylene glycol with a few percent of another
additive. Could be safely washed down the drain.

I don't feel comfortable with that.