I too had that problem
Being a chemist but a part time musician as well I developed a green non toxic liquid to remove the plasticized film and make it look brand new again.. It also conditions the rubberised acrylic coating so it will not return. I should have a video posted on You Tube in a day or so. It takes about 5 minutes per monitor to clean. I haven't determined the platicizer yet but if it is pthylate based it is a plus to get it off as it is a known health hazard. You can reach me at
if anyone has questions. I guarantee you will be impressed with the results and how new they will look. No effect on the sound whatsoever.