Yellowed window frames (nicotine)
From own experience it is really very easy to clean yellowed windows with a good chlorine cleaner.
Even after apparently years of nicotine consumption in the smallest space, we got the window in the house again white. As soon as the cleaner hit the window, the yellow-brown "soup" was already running down. It was important that the plastic is not rough and unsightly after that but afterwards shines beautifully.
However, small parts on the window attract the nicotine and therefore are not quite white, but can be cheaply exchanged.
