The invention relates to removing contaminants from oil using solid sorbents that are comprised primarily of carbon and preferably of coke particles. The coke particles have an affinity for contaminants in oil and are sized to be filtered from oil without plugging. Most contaminants have such a small size that they tend to plug up filters. As the contaminants agglomerate onto the solid sorbent, the resulting particles form a filter cake on conventional filter materials in such a way as to allow the oil to pass on through without significant pressure drop or delay.