Hello oil burners, i wanted to pick some people brains about this topic to finally get a clear answer. What is the safest starting aid to use on a diesel? Obviously ether is extremely harsh, dry and should only be used in small doses, if at all. I remember someone saying WD-40 works great because it lubricates as it goes through the engine, but I think WD-40 uses a non flammable formula now. Lately I have been experimenting with the gas soaked rag trick and it seems to work like a charm, but what kind of damage does it do to the engine? If anyone has any tricks or products they use as starting aids I would be happy to hear some wisdom.