[en] Fabrication of targets of materials which get readily oxidized poses lot of challenges in heavy ion nuclear reaction experiments. Targets of oxidizing elements, viz. Li, Ca, Pb, Nd, Gd, Sm, Ba, Ce, Pr, Bi, Er and Eu have been frequently fabricated in target development laboratory at Inter-University Accelerator Centre (IUAC) in the form of free standing films and foils with backing support. In some cases, foils of these elements are sandwiched between two protective foils to avoid oxidation while exposed to air. Role of sandwiching (encapsulation) in minimizing the oxidation of target surface and its effect in preservation of expensive isotopic targets for longer duration is reported in the present investigations. The level of contamination from parting agents in sandwiched targets is also reported in this paper.