I've always washed my down jackets in the washing machine at the nearby DIY laundrette with hot water n normal detergent because my husband is allergic to the chemicals the normal dry-cleaners use. Through trial and error, I found out that I need to put them, individually, properly zipped and buttoned up, into the laundry bags before putting them to wash. I usually wash 3-4 down jackets together. Then dry them (still in the laundry bags) in the dryer, using only low heat for about an hour. After that, take them out of the bags n lay them flat in the dryer with medium heat for another 30 mins and lastly, with high heat for 15-30mins, depending on the thickness of the jacket. Always so fluffy and smell so clean after.