G'day
I spray mine with silicone spray after every day's riding,if you leave the mud on them they tend to rust underneath it,just make sure it's dry before spraying it,a plastic pot scourer with wd40 will clean of any surface rust if it does get on there. You also can't stop the metal changing coulor when it gets hot,I have had one on my bike for five years and with a little bit of effort still looks good,export brand tyre shine from super cheap auto works a treat,spray it under your mudguards as well helps clean the mud off
Cheers scotty