Methods, systems and designs are provided for removing mercury from crudes. Crude oil is heated to a temperature above 100° C. and held at that temperature for a specified period of time to convert all of the forms of mercury in the oil into the elemental mercury form. The elemental mercury is then stripped from the crude oil by e.g., flashing the hot oil and/or contacting it with a gas phase. This process transfers the elemental mercury from the oil phase into the gas phase. Elemental mercury can then be removed from the gas phase by methods such as condensation, precipitation, or absorption either alone or in combination.