"Waterguard"

A group branding itself "Afya Kenya" one time played a dirty trick on Kenyans. They mixed ash, water and a little salt and sold it to unsuspecting citizens claiming that the mixture would purify their drinking water. And since it did not have any harmful effects the citizens continued enjoying their "waterguard" solution. And "Afya Kenya" made millions from nothing but useless ash. 

Location: Kigetu-ini, Murang'a, Kenya