Old kerosene seems to smoke and soot up a bit more than the fresh stuff.

I keep the fresh kerosene for the heater. Seems to stay prime for a year or two. The oldest stuff, some of it better than five years old, gets fed to the glass oil, and kerosene, lamps I use during power outages. Also the barn lanterns I use outside use it just fine and there are always 'tiki-torches' for cookouts and parties and, of course, kerosene is a lot safer for getting a bonfire going than gasoline.

I also use kerosene for cleaning, guns, bearings and machine parts. It is less hazardous than gasoline and easier on the hands. It can be recycled many times by allowing it to sit for a day or two and decanting the clear solvent off the top. A plastic turkey baster helps. After being used many times kerosene too polluted to be used in any other way can still be used to light that bonfire.

I do the same reuse routine with mineral spirits I use to thin paint and clean brushes. It gets a lot of use.

I don't think I have ever tossed out any kerosene. But if I did feel the need I would consider taking it to the county 'toxic holiday' where they accept limited amounts of household chemicals for free.