How do I get paint to stick to fake wood trim?

I have this trim in my house that is about 20 years old. It is old fake wood-like trim. When I painted some on the window sill it peeled off when it got wet. If I try to sand it, it just gets gritty and this white stuff comes off. I would like to paint it white. Isn't there some kind of cleaner that will take the shine off so that the primer and paint will stick?





Thanks in advance for all your answers!How do I get paint to stick to fake wood trim?
Green Sand Paper will sand the surface without loading with the paint. you can by a de-glosser, or use a good primer.





B-I-N is good primer.





The best Primer that i know of (and would be over kill for this usage) is XIM 400. It will stick to glass.





Water based paint will be more flexible and will be less likely to crack but oil based paints will not soft with prolong contact with water.How do I get paint to stick to fake wood trim?
alcohol based b-i-n primer will stick to it and the paint will stick to that. i have painted glass with the stuff. its the best primer in the world for paint adhesion problems.