In low and middle income settings ash is often promoted as an alternative to handwashing with soap. WHO guidelines currently recommend that ash can be used for hand cleaning when soap is not available. This should be considered as a secondary and inferior option as soap and water in combination are particularly effective for killing and removing SARS-CoV-2. Currently there is poor evidence on the effectiveness of ash for hand cleaning and no evidence that it can kill or remove SARS-CoV-2. It is thought that ash may work by rubbing away (through friction) or inactivating the virus or bacteria (because of its alkaline content).

However in settings where soap is really scarce handwashing with ash is likely to be more effective than hand washing with water alone. If recommending ash to households make sure that they are using the white ash from the centre of a fire once cooled. This white ash is likely to be the most sterile as it was heated at the highest temperature. It is possible that chemicals in the ash could damage the skin, depending on what materials were burned in the fire.

Be aware that handwashing with ash does not feel very nice and does not leave hands feeling and smelling nice in the way that soap does, as such promoting ash may actually discourage people from practicing handwashing. We recommend also reminding people that soap of any type can be used for handwashing. See our section on ‘Are some types of soap more effective than others?’ for more information.

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Author: Sian White
Review: Katie Greenland, Ammar Fawzi
Last update: 20.05.2020