[Bob Carriere]

Locked in moisture can be a problem.......

.....depending on the model some containers do have some kind of water proof vents.... more intended to equalize inner/outer air pressure but not large enough to remove moisture.

I have seen modified containers used for storage of chemicals and "in process" sheet metal and all of them had been retro fitted with ventilation system some passive other had electric fans....... once the air is circulated condensation can be kept to a minimum. It certainly can't be worst than driving your car in a semi heated car garage with a car dripping with road salt every night.

I think a ventilation fan with a solar power hook up would be ideal.

All the Best for the NEW YEAR...

Boob