Firstly you need to clean the ramp, start with windex or nifti, to remove most dirt then some novus 2.  on the actual ball trail I used 1200 grit wet and dry paper then finished with 2000 grit, then novus 2 again and give a good clean up with windex.  You must make sure there is no dirt or dust left on the ramp or this will get melted permantely into the surface. The more time you take now cleaning the surface and removing the ball tracks the better the result you will get. 

First pic is the fist ramp I will attack, it is a little hard to see how bad the ball tracks are in this pic but you get the idea.

Second pic is after cleaning