Some camping blankets, especially those that are coming straight from the factory, may have certain residues on the outer layers that are the result of special chemical treatments that are designed to increase the weatherproofing or fire resistant qualities of the material. While harmless to humans, these treatments might have a lingering smell that you don’t want to take with you to bed. In most cases, a few laps through a low-agitation, cold water washing cycle will eliminate the issue, or even better, a day or two hanging in the fresh breeze.