Wash bedclothes separately at at least 60°C. Germs die and salt and fat will dissolve. No folding, because who cares it won’t make a difference after 1 night. And yeah what elbow said, pull the fittet sheets as far as possible over the mattress. The rubber ring should be as small as possible on the backside. The sewn corners on the bed sheet should rest on the mattress’ corners that are on the underside, or even being stretched further