
A couple of other tips.

1) Make a habit of parking the bike so that instruments are facing away
   from the sun.

2) Meguiar's Mirror Glaze Plastic Polish & Plastic Cleaner. (Cue canned
   product plug #2543):


What you want are Meguiar's Mirror Glaze Plastic Polish and Plastic
Cleaner. They are very mild abrasives meant to remove scratches from
plastic. For fine scratches just use the Polish, for bigger ones start
with the Cleaner and finish with the Polish. The stuff is $5-8 bucks per
bottle at most auto or motorcycle parts stores. Don't choke over the
price too much, since both bottles will probably last you 10 years. The
stuff works great on plastic watch "crystals" and compact discs too.