How can you recognize nonenal?

Nonenal odor has an unpleasant grassy or greasy odor. It is often hard to detect on oneself, but will linger on fabric such as shirt collars and pillow cases. Nonenal odor often persists in confined environments, such as nursing homes, and hence is sometimes referred to as “old people’s smell”. While familiar to physicians in Japan, nonenal remains little known in the U.S. The Japanese have an open and healthy attitude towards aging odor, which they refer to as “kareishu”.

Because it is oil (fatty acid) based, Nonenal is not easily removed by convention soap and water.