A method of removing an oil-soluble metal from a hydrocarbon feedstock comprises passing the hydrocarbon feedstock through a nanofiltration membrane or a reverse osmosis membrane to produce a permeate stream having at least a vanadium concentration less than an initial vanadium concentration in the hydrocarbon feedstock, and a retentate stream having at least a vanadium concentration greater than the initial vanadium concentration in the hydrocarbon feedstock.