Andrew Gabriel wrote:
Bought some extra virgin olive oil some years ago. It wasn't brilliant,
didn't get used very much, and eventually got abandoned in favour of a
better one. Still have two 1l bottles in the garage, long way past the
use-by date, and it's got even worse with age - now smells rather like
oil based gloss paint. (I'm dubious about contamination from the plastic
bottles - only by it in glass bottles now.) Can anyone think of anything
useful to do with it which doesn't involve eating it (or smelling it)?

put a cupful into every tank of diesel.