Metal deactivators, or
metal deactivating agents (
MDA) are
fuel additives and
oil additives used to stabilize fluids by deactivating (usually by
sequestering) metal
ions, mostly introduced by the action of naturally occurring acids in the fuel and acids generated in
lubricants by oxidative processes with the metallic parts of the systems. Fuels desulfurized by
copper sweetening also contain a significant trace amounts of copper.