I'm keen to recycle as much as possible, but my local council provides no cooking oil recycling facility, and it seems crazy to me to put large bottles of oil in the bin for landfill. Would adding used vegetable oil (now dark orange/yellow in colour) in small quantities to my (Skoda) car's diesel tank be likely to cause any damage to the engine or exhaust system? Or is there a better way to dispose of this potential green fuel?