A device and method for the mechanical (partial or total) removal of the liquid phase of the external shell of a core-shell capsule is disclosed. The device comprises a main channel having at least one inlet, one outlet and a tubular element in between, adapted to be operably connectable with a source of core-shell capsules so that these latter can flow throughout said main channel upon application of a pressure or other driving forces; and at least one side channel intersecting the main channel along the tubular element. Upon injection of the capsules inside the device, the side channels peel off by mechanical action the liquid phase comprised within the external shell once brought into contact. The device can be used for production of thin-shelled core-shell capsules such as double emulsion drops for many applications such as food, cosmetic, coating or biomedical ones.