My local launderette is adamant that you can't dry clean a down sleeping bag as it leaves the chemical reside in the feathers and would kill the occupant.
They do a service wash and then dry it in the large tumble dryers with a tennis ball-thing and on a low heat.
sounds like what i know to be how to wash a down bag. Use soap flakes not detergent and down proofing if you like ( helps to keep the down more resistent to wetting out which renders it basically useless and a lot more fagile).
The tennis balls help to break up the clumps that wet down forms speeding up drying and preventing nasty smells and rotting =)
They're right about not dry cleaning but I thought it was because it destroyed the down inside the bag.
The second time I cleaned my old Annapurna, the tumble drying took forever, cost a fortune, and wrecked the stitching of some of the internal baffles. Real shame - the first time was OK, too. Moral is, don't get them dirty and clean as rarely as possible. I think I possibly use a commercial cleaner next time.
If its just a bit whiffy try washing the outer and inner lighly with soap suds that should get any muck and swaet off the marerial, even a good airing out can help.
