I have seen a post of a guy that used Rit dye on his landing gear to change color. He did not specify how exactly how he did it. But the orange example he showed was very vibrant. My guess is with the white arms you could do it.
i'm still waiting for my naza/f450 to arrive but so many ideas in mind... been boiling align heli maingears and using rit dye to color them... thanks.. i'll be ordering extra white arm as spares and might dye them. thanks Ed...