New here, but I hope to change that.
I used to live in an old uninsulated house in Montana, and when we started to move the furniture for a change in the middle of winter, (cabin fever can make you do funny things), we found there was mold on the walls behind the dressers and such in the cooler rooms that had outside walls.
We talked to the landlady about it and she said it was not a new thing, all the old houses she had grown up in did the same. She said move the furniture out and scrub the mold off, I think she said use vinegar, and then put a fan in the room until the wall was good and dry and then keep the furniture a couple of inches from the wall. She suggested we put a piece of 2x4 against the wall so that things didn't get pushed back. I think that is actually only 1.5 inches.
Tried it. Sure enough, it was not a problem after that. It is all about air circulation and keeping
from building up on the wall.
I don't know if this helps, but it is cheap and easy to try. I will be adding an introduction and some other ideas a little later.
Good Luck
Rod