You might be able to sand them lightly to remove the high spots, then paint the panel with SEM Color Coat. Anything else will probably give you a difference in sheen. They are probably ABS, and solvents do not affect it to any degree.
1991 OCC 461 (.030 over 454) BBC, 3.23 posi, flash to pass, drop spindles & springs, Impala rims, Hydroboost, Recaros, MOMO/wood SW w/QR, custom wood shift knob, Pioneer DEH P77DH
1992 OCC now with 5.7 tbi, DEH P77DH
For a parts list, check https://www.impalassforum.com/vBulle...ion-parts.html