The best way to wash a down sleeping bag is hand-washing. Due to its size, your bag should be washed in a bathtub. Use warm water (max. 30°C) and add a gentle, non-detergent soap, ideally one that is made for washing down-filled items. Immerse the bag and gently work the soap in, and then let it soak for 10-15 minutes. Drain the tub and press out the remaining water. Now rinse it thoroughly with cold water. Let it sit for a few minutes. You may have to repeat the process multiple times until all soap is rinsed out.
Some manufacturers allow their down sleeping bags to be machine-washed. Make sure your laundry machine allows, at least, 10kg of load and only use a gentle wash cycle and cold water (or according to the care label) as well as soap made for machine-washing down-filled products.
Air-drying is the safest way. Shake the sleeping bag regularly to spread the fill or tap the down clumps to help rebuild the loft. Never put the bag in direct sunlight. Air-drying takes a long time (up to two days), so you can alternatively machine-tumble the bag after letting the surface air-dry. Use very low or no heat at all. Check periodically to make sure the shell and the insulation are not overheating to prevent melting. When the bag is nearly dry, add some tennis balls to break down fill clumps and to restore the loft.
Washing and drying your Synthetic Sleeping Bag
Synthetic sleeping bags should be washed and dried the same way as down bags. The preferred and gentlest method is hand-washing, but you can also machine-wash it at a gentle cycle at max. 40° and with a mild detergent. Make sure all detergent is rinsed out and