the operation is being carried out so long as the plug 20 is not completely dissolved until after the operation is completed in another exemplary embodiment the thickness of the plug 20 may be sufficiently thick and the soda content sufficiently low such that the plug 20 barely dissolves even in the presence of water to guarantee that a required operation is completed before dissolution in an exemplary embodiment shown in fig4 to advance the dissolution of the plug 20 at least one fluid port 40 or a plurality of fluid ports 40 may be provided in an area circumferentially surrounding the plug 20 water or heated water may be provided to the plug 20 at a time when the plug 20 is to be dissolved the temperature of the water and the time the plug 20 is exposed to the water may both be selected to dissolve the plug 20 in a desired amount of time the fluid ports 40 may be arranged such that the water or heated water is directed towards a portion of the plug 20 that is desired to be dissolved first in yet another exemplary embodiment as shown in fig5 a 5c the plug 20 includes a protective oil based layer 50 deployed.