If you could give us a pic it would help...but any acidic cleaner used contunously has the potential for eating away at the glazing,that's why for daily cleaning we like to use a ph neutral cleaner.Now, what's the chance of the streaks being hard water, or mineral wash off from well water, or the cleaning of the walls.Maybe a spot cleaning with clr, or a similar cleaner for hard water might clean it off.Now, have you been using scrub pads, or something that could have been wearing away the glaze?
