In order to resolve the problem of infinite forces and renormalizability of the self-energy of point charges in non-uniform local dielectric media. The authors propose a formalism based on a nonlocal dielectric function. Implications for both solid-state physics and chromodielectric models of QCD are discussed. The formalism to calculate the energies of systems of charges is developed. The (integral) equation for the Green function is explicitly solved both for a lowly varying dielectric medium and for the planar boundary, and the results are compared with those of the local approach. In agreement with the findings of Baker and Zachariasen (1981), they find that the generic infrared form kappa varies as k² (k² to 0) causes linear confinement of opposite charges, but does not produce the usual flux-tube field configurations.