No need to gass schools just because a few Steatoda Nobilis spiders.
They don’t bite even when handled.
But don’t you guess a dog will bite if you mishandle it?
Spiders in the cold season seek to gain entry into buildings, and some like it there so much, they prefer to remain indoors. Think- no rain, no birds, many insects, and always warm temperature.
Do you know there are myriads of insects inside homes even if you don’t see them? Every carpet will have countless dust mites. They eat skin particles and sweat from clothing, food dusts and all sorts of debris.
So vacuuming everything each day + wiping surfaces with toxic disinfectiants such as Lysol and Dettol is not really good. Bacteria after some while will develope resistance and they will even eat the Dettol.
Every two weeks is enough, plain water with a very little glass cleaner for surfaces is the best.
Do you know you can reuse these spray bottles many times?
You only need to buy a bottle with some cheap detergent, and dillute it 1:10 or 1:20.
Bad hygiene comes from eating unhealthy foods. Wiping surfaces does not really give a helping here.