Prevention first: cut in two stages (snip proud of the part, then flush-cut the stub) so you never crush the plastic. Then sand what remains through a grit ladder — 400 to erase, 600 to smooth, 800–1000 to blend — feathering outward so the repair disappears into the surface.
On unpainted builds, finish with a 3000+ polishing pass or a fine sanding sponge to restore the plastic’s sheen. If you see a white stress bloom instead of a bump, sand lightly — it is deformed plastic, not residue, and light abrasion removes the top layer.
Go deeper in our nippers & cutting tools guides.