Aaargh!!
I thought I had saved/bookmarked this thread and would get email notifications when someone replied. I didn't realize there were all your replies here. Sorry for dropping off and not replying and especially THANK YOU for all the insights.
I'll recap the story's conclusion here:
I tried do dry it with just a fan blowing warm central heating air from a nearby register, it was humidity between 16% and 23% so it was dry as a bone (to which my chapped extremities can attest). After a day I sealed it in a plastic sack with the desiccant pouches I showed in the pic above for one more day.
Then I plugged it in and tried to run signal in the "Combined" (chained channels with mono input) mode and it was producing drop outs and crackles, particularly when a pot was twiddled. It also produced a ticking sound that I could not identify as a compression artifact (although in fairness the comp is pretty wicked complex and I don't know how to use it). I didn't do the alcohol soak as I was leery of removing sealants (or sumsuch something).
After a day of fiddling and crackling I contacted the seller to request a refund and they immediately agreed. They also provided a free-to-me return shipping label. I've mailed it back carefully packed in a box better than what it arrived in.
As to the cause of the water? The plot thickens!
When messaging with the seller, apparently two different people were replying from the same seller's account. One said that it must be rain (but I'd already indicated to them that it couldn't because the packing and box outside weren't wet.
The second person messaged me that they'd split coffee on the DC24 and then wiped it off, but that 'it wasn't much coffee'. That was a heck of a lot of liquid in/on the DC24 tho! And the unit didn't smell like coffee. It smelled like 1988.
The weird thing is that I agree with
@TJTex that it *really* looked like condensation. But I let the gear warm up to room temp before opening. I realize said "immediately upon opening" in my OP but I should have clarified that I meant the closed box equilibrated to room temp first and then when I opened it I already saw the condensation, it did not develop over time after opening. I wait a couple hours (or more) for gears arriving to warm equilibrate to ambient temp. I never open them immediately for the reason you describe. Having said that, the box was jacked up. It was ill-fitting and ripped in a few areas. So some condensation could have gotten in. But, wow... I cannot believe that the amount of water I found can condense in in the dry climate. I buy way too much gear and I've never seen that before.
I guess I'll never know, was the coffee split incidental to the real cause? Did it cause a chain reaction of warm coffee'd gear getting into a cold deliver vehicle in a ratty box? I'm stumped.
Thank you all again!
PS- I've got another one from a different seller that just arrived today, so this story may end up with a happy ending before too long.
