How to restore my bumpers to former glory?

[Apolan]

Hi!

Because my car has changed hands many times before it got to me, the bomper hve gotten red from the original black-plastic-unclored..

as i want to make the car to look stock, i would like to "scrub" the paint off the bumpers, make them black again.. maybe paint the top in color and leave oly the bottom black.

But i dont know how to recondition them? Should i sand-blast them or what? And i dont want them to be smooth and shiny black, so i would like not to color them, or i dunno use black- very mat color?

please do advise.

tnx,s.