The local clouding of glasses after dishwashing near the mouth rims on a coffee pot made of borosilicate glass, on a wine cup made of lead crystal glass & near the stem base on a wine cup made of barium silicate glass has been found to be due to damage during manufacture. The examined clouding is different from the two well known types of filming & etching cloudiness related to the reactions of glass with water & detergent in the dishwasher. The intensive study on the wine cup of lead crystal glass shows that a phase separation was induced during the flame treatment on the sharp rim & base. The aggregates of Pb-rich spheres scaled off when the thin covering of SiO2-rich skin was eroded away & consequently holes were formed on the glass surface on the micrometer scale, which resulted in light scattering & the clouding of the glassware.
