DISHWASHER DISCOLORATION
My 1987 WP DW with plastic door and my 1982 KA KDSS20 which has several white plastic parts shows no discoloration at all. I do use chlorinated detergents about half the time. I repair DWs for a living and the majority of the machines we work on have plastic tubs I seldom see one with any discoloration in fact the plastic DWs usually look better than the SS tubs.
My 1987 WP DW with plastic door and my 1982 KA KDSS20 which has several white plastic parts shows no discoloration at all. I do use chlorinated detergents about half the time. I repair DWs for a living and the majority of the machines we work on have plastic tubs I seldom see one with any discoloration in fact the plastic DWs usually look better than the SS tubs.