Any good de-greaser will clean it. I've used formula 409 or Fantastic in a pinch.Not sure about the oil though I usually run out of the cleaner first.I'll bet you could use WD40.
Good lord, do NOT use WD40. It is not an oil or lubricant.
Be careful if using hot water that it is not too hot. The filter media is 100% cotton and can shrink pulling it away from the filter frame. I always use cool water when washing and rinsing mine to be sure I'm not damaging the cotton.