Silicone Oil Removal

Q. Would a phosphoric-acid-based cleaner remove silicone oils from a metal surface? –A.J.

A. No, since phosphoric acid is essentially water based, and silicone oils are not soluble in water, you will not see any appreciable removal of silicone oil from the metal surface.  If you are expecting the silicone oil to degrade in the presence of the phosphoric acid, this is also not very likely to happen due to the relative stability of silicone oils. Silicone oils generally have very low surface tension and even an aqueous cleaner with a very good surfactant mixture will likely not be very effective at removal.

You will want to dissolve the oil with a solvent to remove as much as possible.  Most aromatic (ring structure) solvents are effective at dissolving silicone oil.  These include toluene, xylene and naphtha.   Additionally, silicone oils are reported to be soluble in chlorinated solvents such as trichloroethylene, perchloroethylene and methylene chloride.  Polar solvents such as alcohols and acetone will not be effective at dissolving silicone oils.