Autoignition is not spontaneous! • AVE Almost Burned My Shop Down! Oil...
More rigorous test of oily rags catching on fire:
Toxic amounts of phenol at low temperature 230F 110C
Can take a long time, depends on ambient temp. 2436 hrs at 60F 15C.
Carbon Monoxide may aid ignition
Cotton faster than paper.
Prodigious amounts of smoke prior to ignition
@DDSpeedShop