Solutions of solvated electrons in the presence of magnesium make possible the surface modification of halogenated polymers such as PVDF, Viton(R), PCTFE, PVC or PVDC. The magnesium treatment which is milder than that using solutions of solvated electrons in the presence of alkali metals results in defluorination and/or dechlorination of the halogenated polymers. In the case of PVDF, it was demonstrated that (i) the surface free energy and consequently the hydrophilic character of the surface increased slightly with defluorination; (ii) anion radicals could also be used as reducing species; and (iii) copper or nickel metallization of magnesium treated samples could be achieved with the electroless procedure.