Is handwashing with ash safe? - Does it kill any viruses?


  • goeco
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  • Self employed innovator with an interest in wastewater treatment systems and recycling of nutrients
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Re: Is handwashing with ash safe? - Does it kill any viruses?

Hi Elisabeth,

sodium hydroxide is caustic soda or lye. Lye dissolves greases. White wood ash contains potassium carbonate, or potash, along with calcium hydroxide, but very little if any sodium hydroxide. By adding water to white wood ash, the calcium hydroxide and potassium carbonate react, forming caustic potash (ash lye, potassium hydroxide) and calcium carbonate (please somebody correct me if I'm wrong, I'm not a chemist!).

On this basis I have always assumed that handwashing with ash and water means handwashing with ash lye. I wash my hands with wood ash, which is particularly effective at removing greases and hard-to-remove dirt. Ash will remove just about anything from hands, and it certainly is not painful to use and it doesn't burn skin. Well, not mine anyway...

I'm asking whether it's appropriate for people from the developed world who like the smell and feel of soap to impose their paradigms on those with different practices...  Habits are also influenced by tradition and availability. If someone washes their hands effectively with wood ash and has always done so, because they are happy with that practice and use their own resources, is it right for someone to come along and say "you should use soap, it will feel nice on your skin and make you smell nice."?

Dean Satchell, M For. Sc.
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  • sianwhite
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Re: Is handwashing with ash safe? - Does it kill any viruses?


The statement in our post that says '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' is based on research that I and others have done in several countries exploring soap products and ash. This includes work done in DRC, Ethiopia, and Nigeria - all settings where ash is commonly promoted by NGOs and quite widely used in some regions. This sentiment reflects the sentiment of populations who, across these countries, consistently rank ash as the least desirable option for handwashing. The fact that it continues to be used widely is much more a factor of poverty and inequality. In fact people often directly said that ash is perceived as something only poor people would use - a label that understandably they did not wanted to be associated with.

In general I am not familiar with organisations promoting the use of soap and discouraging the use of ash. In most cases handwashing with soap is promoted and organisations explain that if soap is scarce ash can be used instead. However at the moment I think this is an imperative to actively encourage people to use soap where possible because we know that it can effectively destroy and remove SARS-CoV-2 from hands. While it is plausible that ash may be able to do the same we have no evidence to suggest this at the current time.

I hope that helps

Sian White

Research Fellow
Environmental Health Group - Faculty of Infectious and Tropical Diseases London School of Hygiene and Tropical Medicine

Find out more about the Environmental Health Group at: Find out more about the Health in Humanitarian Crises Centre at:
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