You may be able to hone the roughness off, it may just be residue from the decaying O rings.
You might try MEK, if you can still find it. If I remember correctly, the Poly-Fiber products are thinned with MEK.Next step will be to wipe it all down with acetone to remove any remaining residue. Once that's done, I'll need to inspect every inch to find places where bare metal might be exposed, either from inadequate powder c
Ralph