CaF2 fine powder and films were treated with the Lewis acids SbF5 and BF3 to create a strong driving force to draw F- ions out of the boundary regions according to L (surface) + F-F (boundary) --> LF(-) (surface) + V-F(.) (boundary) (L = SbF5 or BF3). The conductivity results of polycrystalline ceramics treated in this way indicate a significant enhancement of the ionic conductivity with a slope that is characteristic for F- vacancy migration. The impedance spectra of the CaF2 films showed two semi-circles of the impedance spectra after the acid adsorption. Judging from the microstructure, the high frequency are is attributed to bulk conductivity plus interfacial contributions being in parallel with the bulk pathway and the low frequency semi-circle is characteristic of the blocking effect due the grain boundary core structure and the gas adsorbates therein being perpendicular to the current flow. A quantitative estimation of the enhanced conductivity assuming space-charge effects is compatible with the enhanced conductivity results.