The time has come to wash my down quilt (8 years, I am way overdue). The first thing to do is to buy a jug of a special cleaner made explicitly for down gear. Granger and Nikwax both make superb and widely endorsed products. Read the directions. Do not use "extra" product for a cleaner result. Residue is as bad or worse than dirt.
If you don't have a front loading machine, you are going to either have to go to a laundromat (you may need to anyway if your bag is too big for your compact machine) or you will have to hand wash in your bathtub. I won't get into the bathtub routine except to say, read the following paragraph about handling water soaked down and be really careful; squeeze out all the water you can before moving it out of the tub. A machine is really the way to go.
I am going to use my front load machine to wash my Jacks R Better down quilt, and I am going to use extra rinse cycles. If it isn't clean, I will wash it a second time, perhaps spot treating difficult areas as per the instructions.
Take special care when you take the water soaked bag out of the washer! Heavy water soaked down can rip out the baffles in the bag. You want to gather it up and cradle it to move it into the dryer. Spin all the water you can out of it in the washer.
Drying will take a long time. Be patient. Be sure to fully dry it. Use very low heat or no heat at all and have other things to keep you occupied. It may take the entire afternoon. Heat is a deadly enemy, but some warmth will speed up the process. Toss in several clean tennis balls as the process finishes to help break up down clumps and/or carefully pull them apart with your fingers.
I have read complaints that the bag smells terrible after being washed. Perhaps you should have washed it sooner? Perhaps you should wash it a second time? Mine was not like this at all. If yours is, they say that once it is truly dry this will all go away. If mine smelled really bad after washing, I would probably wash it a second (or even third) time. Whatever it takes. Wet down should not smell.
At any event, you must be sure it is fully and completely dry before you store it! A damp bag will mildew and be horribly damaged.
Not fully drying a bag is perhaps the worse thing you can do. It is probably going to take 2 hours in the dryer with no or low heat.
I try using my home front loader. The quilt is full of air and just sits in one place. This is not going to work. 100 ml of soap wasted. I shove the wet thing in a 5 gallon bucket and head for the laundramat. It goes into a 30 pound front loader. Another 100 ml of soap and $4.00 of my money. It takes a while to get wet, so a fair bit of the wash cycle may be only semi-effective, but by the time the rinse cycles are going, it is getting tossed around like it should be.
A side note. If I had all of this to do over, I would start by hand washing it. The idea would be to get the thing saturated with water and all of the air out of the thing. Then it would fit nicely into my Kenmore HE-5t front loader at home.
As the washer finishes at the laundramat, there are still bubbles on the window of the washing machine. This worries me. Maybe it shouldn't. But I want to rinse it further. I put it back in the bucket wet and take it home. Now I run it through a full wash cycle with no soap, just to give it a thorough rinse. It is now 1/3 the volume it was when I first took it to the laundramat and easily fits into my home machine and the machine handles it properly. I select the highest spin speed to get as much water out of it when it finishes.
My home dryer got it maybe 95 percent dry in an hour our so on low heat. More time was needed. I took it to a huge dryer at a laundromat, hoping it would flop around in it and get dryed better, but it did not - even with 3 balls in with it. So I may as well have just continued drying at home, perhaps with no heat. It is late August in Tucson and I am going to let 110 degree heat in my workshop finish the drying, but check by hand for down clumps that need to be broken up.
What I notice is tha the entire quilt seems fine, except for the baffle at the head end where there is a fair amount of down clumping. My guess is that the down in this baffle has absorbed a lot of oils from my skin (this was the dirtiest part of the quilt) and that one washing has not straightened all of this out. The only way to know will be to wash it again soon and see if there is improvement.
As a note, some people recommend putting two tennis balls in a sock and throwing a couple of those in the dryer. The claim is that these stay active more and solo tennis balls get trapped in the sleeping bag and are "out of circulation". I am looking for something a bit more massive. My tennis balls all went out of circulation.
Tom's hiking pages / tom@mmto.org