Dull plastic window frames again shiny
Dull plastic window frames are again beautifully shiny, if you after window cleaning (the window frames should not be forgotten) give some fabric softener on a soft cloth and massage into the plastic frame.
I myself do this every few years, in which I then put a bowl on the window sill and then work piece by piece of the frame - if you always take the bottle to hand, you just have too much fabric softener on the cloth or frame and polished then a wolf.
I used to take Vaseline for it - it was okay too. But then a colleague gave me the tip with the fabric softener and since then, my window frames shine as late as the spring cleaning always like brand new.