In reply to m0unt41n:
I just cleaned my mountain equipment down jacket this weekend. I put it in the top loader washing machine on cold, and then put it in the tumble drier on the lowest heat setting (no fabric softener). if my washing machine had a "gentle" setting I would have used that too.
I had to run it twice through the drier, and I separated out some of the "clumps" that i could feel in some of the panels between spins. It's come out clean, and perfectly puffy, with no clumps remaining.
I'll admit to having been a bit nervous beforehand, but they're the instructions sown on to the jacket. maybe i got lucky..