Car oil I understand.. But surely veg oil, assuming it is derived from vegetables (??) is compostable, or at least doesnt need any special method of disposal?
Used vegetable oil is commonly used in the cosmetics industy...not sure they'd take in such relatively small quantities though, so the recycling centre is the way to go.
Leo
If it has been used in cooking, it will contain animal fats and thus will positively not be compostable unless suitable treated (or you like rats for company).