Methylene chloride (according to compatibility references) is not highly reactive with these metals.  However, methylene chloride will slowly hydrolyze with water from the air to form hydrogen chloride (hydrochloric acid) which will attack all of these metals.  In addition, methylene chloride is a disposal problem.  Chlorinated solvents (chloroform, methylene chloride, carbon tetrachloride, perchloroethylene, et al) are subject to very stringent government regulations on handling and disposal.

Have you tried methyl ethyl ketone or tetrahydrofuran.  These may also work for softening the epoxy  Please also note that it is virtually impossible to dissolve a cured epoxy.  It is a cross-linked polymer and impervious to almost all solvents.  I do not know what you mean by "silicons" as this term applies to the metal.  Do you mean silicones?  Silicones are fairly easily removed with any of the solvents mentioned above.

Keep a careful eye on the development of the oxide layers in St.Steel and AL.