Is it silver or aluminium?
Actually glass blasted steel (cause the mat centre section
might collect rust if
totally neglected
), except those models/years where the spoked area is painted in mat gold metallic.
I use an old toothbrush with a dab chrome-polish to get those spokes back to shape and they hold up/rust free
quite well, so never painted some (at ~120Tkm/75Kmiles they "expire" anyway, so not worth the hustle...
)
Hint: don't forget the paper-spacers when bolting them back on the wheel!