From my understanding, you want to turn "plastic" into real cash. 

The mold and mildew was throughout the rooms of the house.At some point, someone decided there was not enough ventilation and the "fix" was to close off the vent ducts, lay plastic on the ground, and install dehumidifiers.

Clays shrink and swell depending on their moisture content/plasticity and you don't want your foundations to do the same.

I have 12 properties and my paper is limited to mostly two little briefcase sized plastic paper organizers with multiple pockets. 

Or worse, once I had the vinyl around the glass cracked by 2 big roofing nails pounded in to hold the plastic shower curtain as a blind.

Get metal silverware, not plastic with metal. 

In any of those cases put plastic over the floor & doors and tape them down around the edges and you can work with the windows slightly open for air flow.

Only thing I can think of was that we left some empty  plastic water bottles (not a place with drinkable tap water) on the counter because the trash cans were full. 

They don't make plastic screws/nails yet! 

I had to water proof a couple of places in Seattle where it can occasionally rain (for weeks at a time ;-) One place was located near a stream.We dug about 3 feet deep around the foundation, we used concrete sealer on the concrete inside and out, placed a thick layer of plastic against the concrete & back filled to about within a foot of the surface and installed a "french drain".