Remove the queen-sized comforter from the duvet cover (if it has one). Check the "care instructions" tag on the comforter to see if the comforter is able to be cleaned by hand or if it is dry clean only.
Fold the comforter into a small square bundle (if the comforter is dry clean only). Place the folded comforter into a breathable plastic bag before bringing it to the dry cleaner to avoid dirtying it further.
Place the comforter in a commercial-sized washer (if it can be machine washed). Avoid washers with an agitator, as they will cause unnecessary wear on the cloth of the comforter. Use specifically labeled "Gentle" detergents. Wash in the gentle cycle of the washer.
Dry the comforter in a commercial dryer in the tumble dry cycle. Repeat the tumble dry cycle as many times as needed until it is completely dry. Hang in a well ventilated area if air drying. Allow anywhere between 8-12 hours for a complete drying. Run a hand over every part of the comforter to locate any wet spots (if any). Replace the duvet cover and spread over the queen-sized bed.