How to Wash an Oversized Comforter. Many homeowners use oversized comforters for large beds or cold winters, but they have trouble washing them in their household laundry machines. You may use a duvet cover that is easily taken off and cleaned but often a comforter is already too large and fluffed on its own. If your bedroom comforter is too large for your washing machine, follow these steps to keep your blanket clean.
Repair any holes or tears in the fabric before washing to avoid losing the fill. Spot treat any stains before washing as well, making sure to follow the treatment's guidelines.
Find a large commercial-grade front-loading washing machine at a laundromat and have enough quarters for a wash cycle.
Wash the comforter in a delicate cycle using non-chlorine detergent and cold water. Read the label for specific care instructions.
Use a large commercial dryer on low or medium heat, again making sure to have enough quarters for extra drying minutes when using a low heat cycle. This might take several hours but is better than using high heat, which could damage your comforter.
Throw a tennis ball into the dryer with the comforter to keep the fill moving.
Dry thoroughly to prevent mildew. Check periodically to assure the comforter doesn't get too hot and burn.