I've had this question on my mind for some time now.
Is shine:
(1) the result of your finger oil's sticking to the caps;
(2) the result of constant use rubbing away the texture on top of the caps and kind of "sanding" it down to a shine; or,
(3) a combination of both?
2 makes more sense to me, because PBT, being a stronger material than ABS, is more resistant to shine. If 2 were true, then it's because PBT is harder and thus not as easy to sand/polish down to a shine with your fingers.
Any thoughts? :3 For keyboard science, of course.