Abstract: A process is described for the extractive oxidation of contaminants present in raw fuel streams rich in heteroatomic polar compounds and catalyzed by iron oxides contained in natural limonitic goethite, said process comprising contacting said streams with an oxidation pair which is a peroxide in solution/organic acid in amount of at least 3 and an amount between 0.01 and 10 wt % of an iron oxide, both based on the feed, the iron oxide being made up of a reduced natural limonitic goethite. The goethite reduction by a hydrogen stream has the advantage of lowering the migration of non-contaminating polar hydrocarbons from the fuel stream to the aqueous phase, at the same time obtaining higher mass yield of final product fuel while the level of target contaminants to be removed is maintained relative to the state-of-the-art process. Process yields attain 98% weight/weight.