A method for removing a trace amount of mercury in a crude oil feed, comprising: providing a crude oil having a first concentration of mercury in which at least 50% of the mercury is non-volatile mercury; mixing into the crude oil an effective amount of a water stream containing at least a water-soluble monatomic sulfur compound selected from the group of sodium hydrosulfide, potassium hydrosulfide, ammonium hydrosulfide, sodium sulfide, potassium sulfide, calcium sulfide, magnesium sulfide, and ammonium sulfide and combinations thereof forming a mixture; extracting at least a portion of the non-volatile mercury from the crude oil into water as soluble mercury sulfur complexes forming a mercury rich wastewater; and separating the wastewater containing the soluble mercury sulfur complexes from the crude oil for a treated crude oil having a reduced concentration of non-volatile mercury; wherein percent volatile mercury is measured by stripping 15 ml of crude or condensate with 300 ml/min of nitrogen for one hour, wherein stripping is carried out at room temperature for samples that are fluid at room temperature, at 60°C for samples that have a pour point above room temperature but below 60°C, and 10°C above the pour point for samples which have a pour point above 60°C. providing a crude oil having a first concentration of mercury in which at least 50% of the mercury is non-volatile mercury; mixing into the crude oil an effective amount of a water stream containing at least a water-soluble monatomic sulfur compound selected from the group of sodium hydrosulfide, potassium hydrosulfide, ammonium hydrosulfide, sodium sulfide, potassium sulfide, calcium sulfide, magnesium sulfide, and ammonium sulfide and combinations thereof forming a mixture; extracting at least a portion of the non-volatile mercury from the crude oil into water as soluble mercury sulfur complexes forming a mercury rich wastewater; and separating the wastewater containing the soluble mercury sulfur complexes from the crude oil for a treated crude oil having a reduced concentration of non-volatile mercury; wherein percent volatile mercury is measured by stripping 15 ml of crude or condensate with 300 ml/min of nitrogen for one hour, wherein stripping is carried out at room temperature for samples that are fluid at room temperature, at 60°C for samples that have a pour point above room temperature but below 60°C, and 10°C above the pour point for samples which have a pour point above 60°C. mixing into the crude oil an effective amount of a water stream containing at least a water-soluble monatomic sulfur compound selected from the group of sodium hydrosulfide, potassium hydrosulfide, ammonium hydrosulfide, sodium sulfide, potassium sulfide, calcium sulfide, magnesium sulfide, and ammonium sulfide and combinations thereof forming a mixture; extracting at least a portion of the non-volatile mercury from the crude oil into water as soluble mercury sulfur complexes forming a mercury rich wastewater; and separating the wastewater containing the soluble mercury sulfur complexes from the crude oil for a treated crude oil having a reduced concentration of non-volatile mercury; wherein percent volatile mercury is measured by stripping 15 ml of crude or condensate with 300 ml/min of nitrogen for one hour, wherein stripping is carried out at room temperature for samples that are fluid at room temperature, at 60°C for samples that have a pour point above room temperature but below 60°C, and 10°C above the pour point for samples which have a pour point above 60°C.