Thanks but that thread seems to reach the conclusion that it is either good or bad but reaches no firm conclusion so I still am not sure whether I want to wash by down bag using down proof. I washed a cheaper down bag with down proof a few years ago and I thought that the bag was not as warm afterward but I was not sure since it is hard to tell just using "gut" instinct. I will probably just wait until my down bag gets even dirtier than it is now.