From what I've experienced, a fuel like kerosene should burn OK regardless of age as long as it used in a wick type device. I've burnt kerosene that must have been sitting around in our garage in an old 5 gallon metal gas can for 10+ years in a wick type heater without problems. It could have just been a fluke or we may have just been lucky, dont know but it worked for us.Seems like that would be a handy thing to have, since fuels (like white gas or kerosene) do not keep forever.
I wonder if using rancid oils would cause a problems?This old thread covers olive oil lamps, when I first joined I made one for fun out of stuff I had around...jar, wire, cut up T shirt for wick. But as is pointed out in thread, unless olive oil is all you have, it's too expensive to use, and if it's California extra virgin olive oil it's liquid gold right now.
Good question, all I found is a guy talking about using it and that it might give off an odor. We go thru olive oil like it's water...part Italian We did have some older Canola oil that was way past it's prime and I used it on the wood handles of my garden tools, just scraped then sanded em and used a rag to put the oil on...but I digressI wonder if using rancid oils would cause a problems?