Don't know if anyone else has had this but cleaning the insides of my windows has left the window runners with white bits on them from the kitchen roll I used which has been driving me nuts. I managed to solve the problem today when doing the usual clean by winding the windows down, then getting some sellotape, wrapping it round 4 fingers with the sticky side facing outwards then dabbing the pesky white bits until they stuck to the tape. Job done.....

Well done