Spontaneous combustion of coal is a well-known phenomena around the globe. Apart from the coal itself. burning coal-shales is becoming a problem in the South African coal mines. Serious incidents of spontaneous combustion have been reported as a result of self-heating of reactive coal-shales. https://www.roneverhart.com/Medline-Remedy-Phytoplex-Z-Guard-Skin-Protectant-Paste-Scented/