We examine various ZnSe spectra to obtain that which best represents the dielectric response epsilon of ZnSe. The measured evolution of pseudodielectric function [epsilon] data with chemical etching shows that the natural overlayer on ZnSe can be modeled accurately only if we assume that it contains amorphous Se. Hence previous assumptions made in correcting [epsilon] mathematically are not correct, and data obtained on stripped samples yield the best representation of epsilon. (C) 2000 American Institute of Physics. [S0003-6951(00)05147-0].