Quoted from jim5six:
I would like to confirm that Rubbing Alcohol (as recommended by Spooky) will not harm the side art in any way, or do I need to remove the rails to clean them?
Removing the rails takes about 5 minutes! Remove the screws, flipper buttons and one bolt with a nut right next to the lockdown bar receiver, then they slide out really easy. Guess it‘s way easier to remove the residue with the rails off the machine. I used steel polish & cleaner, was a bit tedious but took only about 10 minutes per side.
Had to remove them anyway to install the lighted siderail mod, the machine looks fabulous now