I picked up a bottle last week and recently used it on some very old screens. I thought it worked great on the frames, but didn't 'eat' the dust as much as I was looking for.
I even laid it on pretty thick, but after they dried I took a brush to them and tons more dust came out. I believe this product works, but I was not impressed with how it left so much dust in the screen, even with a thick coating. (I was expecting magic for that price)
I think I'll stick to just using this on the not-so-dirty screens.