i bought the 2/3 red taillights for my lexus ls 400 a while back and they are real nice lookin. however, today i noticed my left taillight, on the corner, is a duller color than the rest. i tried to see if it was dust by putting water on the outside, but it still looks the same. what can i do to get the color back to the original color? thanks for your help in advance.

alex