Thermal currents have been obtained from corona‐charged Mylar films exposed to a humid atmosphere for variable times. A theory that we have recently developed to account for the current ``spectrum'' of these ``near surface'' charged specimens is put into a form that facilitates routine analysis of the peaks. Exposure of Mylar to 100% RH at 50°C has a drastic effect on the four traps previously reported. After 5 days, they have completely disappeared, and only 0.6% of the total initial charge remains. Ninety percent of this latter charge is held in a trap at a depth of 2.6 eV, and the remainder at 1.3 eV. Assuming that the traps empty under monomolecular conditions, trap densities are of the order of 1014/cm3, and mobility‐lifetime products, 10−8cm2/V; to be compared with 1016/cm3and 10−10cm2/V for the dry samples. The thermal current spectra show, in explicit detail, how humidity affects charge storage in Mylar.