The occurrence of solid salts in pores has well-known damage effects (e.g. [1]). It is here demonstrated that it also changes drastically the topology of the porous spaces and possibly also the properties of the occluded liquid. We performed a series of observations on NaCl precipitation in 75μm cylindrical tubes, evidencing that the solid forms at the liquid-air interface contributing to isolate the remaining liquid column (Fig. 1a). The homogeneous capillary tube is now heterogeneized by the two NaCl 'corks', apparently closing the micro-system on itself. After 6-months observation of such immobile situation, we observed the cavitation of a vapor bubble in the liquid behind the NaCl cork (Fig. 1b). This event demonstrates that the occluded liquid underwent a metastable superheated state, controlled by the very thin capillary plugs certainly persisting, tough invisible, around the NaCl precipitates.