Hey, 
You guys are legends !!  
Thanks for all the contributions !! 
My canopy is now fixed but still has a slight lines (from the scrubbing) but is unnoticable .. :)  
I tried as suggested .. 
had a 1200 sandpaper and give a good scrub (a bit scary especially seeing more scratch marks ..yikes) but that got rid of the smudge. Then using toothpaste (yes, I had some toothpaste lying around ..surprisingly) and gave it a good scrub with a thin tower ..wash and bravo !! ..incredible !!   
Once again, all your help were very much appreciated 
Off to finishing my P-51 ..yippee