Storing tomatoes in ash

I don’t use a fridge here in Nigeria and I have had to learn lots of fascinating ways to keep food, particularly vegetables, so that I don’t have to go shopping too often.  I manage with most things, but keeping tomatoes fresh has always been the biggest challenge.  So I was fascinated to read an article online about a farmer in Burundi who had the same problem, but solved it!  After trying without success to store tomatoes in many substances, he found that using cold ash really worked for him.