Total acid number and/or corrosiveness of a crude or refined hydrocarbon, where the total acid number and/or corrosiveness is due to the presence of acid compounds such as carboxylic acid (naphthenic acid), may be reduced by treating the hydrocarbon with a metallic overbase. The effect of this treatment may be substantially enhanced by the presence of a hydrogen transfer agent. The abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b)