My old DI got fed all sorts of stuff. My workshop was next door to a garage that did a lot of 'wrong fuel' repairs, and due to the costs of disposal they used to give it to me for free - if it smelt a 'bit too petrolly' I'd chuck a couple of gallons of filtered waste engine oil in with it - went about 18months without buying much diesel. The only time it objected was on very hot days, when after long journeys it would boil the fuel in the HP lines - you could hear it fizz - and you'd have to crank it a few seconds before it would go if still very hot, was fine when allowed to cool down.
Did make winter starting a no fuss affair, disguised a shagged battery for months - til I had to put a tank of 'real' fuel in it .....
Jim