[header] How to clean a sleeping bag [title] Use soap formulated for a down-filled sleeping bag, if applicable. [step] Only use soap made for washing down material, as it will be gentle on the stuffing in the sleeping bag. Avoid using regular detergents and soaps, as they are too harsh and can damage the down. 
Look for down soap at your local hardware store or online. [substeps] Follow the instructions on the label to determine how much soap to use.