The present invention relates to a method for purification of oil which is contaminated with particles of random density and/or water. A collection polymer or polymer mixture which is insoluble in oil and liquid at room temperature and which has a density which is higher than the oil is added to and mixed with the contaminated oil. The collection polymer and the oil are separated by gravity with or without centrifugation such that the oil forms a top phase and the collection polymer or polymer mixture and the main part of the contaminants form a bottom phase. The bottom phase with the collection polymer and the contaminants is removed.
