Greasy window screen

davetom

Hi all, How do you all deal with a greasy window screen.? I clean mine with a proper car window spray cleaner which is ok for a while but the window wash, which i have been buying ready mixed from a well known car accesssory store seems to make it bad again.
Its ok when its dry but when raining its very smeary. Now the nights are getting longer driving in  rain, in the dark with a smeary window is not good. Any good ideas i would be grateful for.       

Thanks david