Using a liner—a thin, bag-shaped sleeve, often made of silk—will help keep your sleeping bag clean and also add warmth. When on the trail, try to keep dirt and body oils from collecting in your bag. This is harder to accomplish on long expeditions, but it’s possible if you have clothes that you wear only in your sleeping bag. Also, don’t eat in your bag or your tent—especially in bear country—no matter how tempting it might be.
