Can a dirty sleeping bag isolate dirty things?

You can buy some cloth (preferably elastic) to make a single-layer thin sleeping bag, which doesn't need to be big enough to hold yourself, or simply bring a single thin quilt cover, thus separating your body from dirty quilts and sheets.

Sleeping bags are mainly used outdoors. I think it's enough to go to work all year round and buy a sleeping bag for the night shift. You don't need to add a quilt, but I don't have down. Down can ensure that you have enough indoors. Colleagues' quilts are damp, light, thin and warm. You can put sheets+sleeping bags in the hotel, which is convenient to carry; & If it's in the south, it's as good as a big name. You can cover your own down jacket in cold weather, and the down is hot enough.