Those hard cleaning discs are last resort,before drive replacement. I believe staple's have them on sale.
Try ejecting the tray and spray some compressed air into the stand alone player.
After all those attempts and it doesn't work:
Take note of the area that shows the pixellation,then try testing the backup on some other drives and see how they look.The more drives,the better. Also slap it back into the pc,using the drive that burned it, to do the playing. See how it looks in that suspected area.
This will help narrow down if it is a drive issue or it's a disc issue.