How should I clean a down sofa?

First, check the tag on your furniture to see if it has specific instructions. It's possible your cushions can be washed, but they may need to be spot cleaned, instead. You can use a soft brush attachment to vacuum your couch, which can remove dirt and dust. If your cushions are machine washable, put them on a gentle cycle with mild detergent. If you need to spot clean your sofa, mix 2 tsp of laundry detergent to 1 pint of warm water. Then, dab your furniture with the solution. Additionally, you'll need to toss and fluff your cushions often to break up the feathers, which may clump.