Two winters ago I washed my favorite puffer. Pulled it out of the machine and it looked like a deflated balloon — all the down had clumped into hard little balls in each baffle. I thought I’d destroyed a $200 jacket.

It took three days of intermittent drying and fluffing, but it came back. The jacket is fine. My dignity took longer to recover.

What you’re fighting

Down is a cluster of tiny feathers. When they get wet, they collapse and stick together. Regular detergent leaves residue that makes the clumping worse. The goal is to clean without stripping the natural oils and to dry thoroughly before mold sets in.

Drying is where people give up too early

This is the part that takes forever and separates good results from ruined jackets.

Low heat only. Throw in 3-4 clean tennis balls or wool dryer balls. The balls bounce around and break up clumps as the jacket tumbles. Without them, the down stays in wet wads.

Check every 30 minutes. Pull the jacket out, shake it, manually break up any remaining clumps with your fingers, put it back. Expect this to take 2-3 hours total. If you stop early while there’s still moisture inside, the down will mildew and the jacket is done.

It’s dry when it feels fully puffed and there are no cold spots when you press your hand against the fabric.