The rears are glued on, heat them up with a hair dryer and use some fishing wire/dental floss to gently slide them off. Then use a spirit wipe to clean any glue off.
TBH, go buy some matte black ones from ebay and stick them on.
Painting that plastic/chrome stuff never lasts, and will chip off within a few weeks. The ones on ebay are simply black plastic, so cant chip or flake off.
The rears are glued on, heat them up with a hair dryer and use some fishing wire/dental floss to gently slide them off. Then use a spirit wipe to clean any glue off.