There are many ways to post process a really cool metal print. You can do it by hand, with a tumbler, etc. Some great articles have been written so far about post-processing materials like bronzeFill, copperFill, & steelFill:
Polishing with some basic DYI-tools
htthttps://colorfabb.com/post-processing-gcreate-s-rocket-ship
https://colorfabb.com/let-s-polish
Adafruit's instructional video
Some interesting blog posts about prints not made by us (we did write the blogs, which is the easy job):
Ancient Greek Helmet by Andreas Mielonen: https://colorfabb.com/ancient-greek-helmet
Huuuge Octolamp by Esteban Pacheco: https://colorfabb.com/octolamp