It may have been radiator heat. But still you’d expect some spider webs. Well I don’t have 30 years to shut off a room and try an experiment lol.
When an auctioneer entered the apartment, he found a treasure trove. The apartment, although covered in a thick layer of dust, was like a piece of history frozen in time.
From above link.As they already sold the painting the auctioneer probably already had a cleaning crew in there.
You are right on radiator heat. Thats what we had on the farm, 100 year old home, no spiders but lots of mice. I had traps sent all over the house. My dog would hear a trap snap shut and off she’d run checking the traps. I told my dad that those dam mice would do square dancing in the dining room.The house was in good condition, wood floors etc. Radiators in every room, but the mice could find very small spaces to get in the house. Should have had a house cat, but hubby was not a cat friendly kinda guy.