There comes a time in every trampers life when they look at their sleeping bag and think wow, that thing stinks/is much thinner than it used to be/has burn marks in several places. Do not fear, you can return even the saddest looking bags back into lofty goodness with half a bottle of down wash, a couple of sock balls and oh about 9 hours of your life. Washing your down bag is somewhat of a marathon effort and you should first seriously consider paying to have it done by a professional while you make better use of the time . Also, you will be needing a dryer and a bath so perhaps start by scoping out which of your friends possess both and offer to water their miniature cactus next time they go away for a long weekend.
My Mountain Equipment 3 season bag had experienced moderate use over the last 6 years and I was starting to feel a few cold spots where the down was clumping together. This is caused by dirt and the natural oils from your body getting into the down - another good reason to use a sleeping bag liner. In order to return the down to it's former prime it needs to be washed with a product that will clean the dirt away but not deteriorate the down itself, this is where Down Wash comes in. I used Nikwax which you can buy in a 300ml bottle for $19.95NZD and it washed two down jackets and my sleeping bag.
Fill the bath with 4cm deep "hand hot" water and add 3 cap fulls of the Down Wash.
Turn the bag inside out as any water resistant coatings are generally on the outer shell and will make it harder for you to get the bag properly soaked. Submerge the bag in the water and gently knead the baffles to allow water to seep in through the stitching. Leave for 5 - 10 minutes to soak.
Rinse the bag in cold water two to three times until the water runs clear. Gently squeeze as much water as you can out of the bag before transferring to the dryer. This is a lot easier with two people as you need to support the bag when wet - they generally aren't designed to carry the extra weight of all that water.
Step Four: position dryer in easy-to-access spot since you're about to spend the rest of your day with it. Place sleeping bag and sock balls in dryer and set for one hour.
Step Five: Remove bag from dryer and tease clumps of down apart from within each baffle. This is a most tedious process so I recommend watching a movie or in our case the replay of the All Blacks quarter final thrashing of the French in the Rugby World Cup. Work your way from one end of the bag to the other working out each lump before returning to the dryer for another hour.
Step Six: Repeat Step Five until there are no more lumps and the baffles have regained their loft. We ended up doing this four or five times until it was completely dry.
As an additional note, the emergency tape I put on a few burn holes 4 years ago (got a little too close to the fire) became heat sealed to the bag whilst in the dryer forming an excellent patch, nice.
How to make a sock ball
Tie a knot in one end of a sock then roll it over on itself, twist and roll back on itself again. Repeat until you run out of sock and then add another sock and continue until it forms a ball. Show your friends how great your balls are.