To clean an FDM 3D model, first remove support structures with pliers or a hobby knife, then sand layer lines with progressively finer grit sandpaper (120–2000), and wipe the surface with 70-90% isopropyl alcohol to remove dust or residue.
Support removal gets rid of excess material—PLA supports often snap off easily, while ABS may need careful cutting to avoid damage. Sanding smooths rough edges and layer lines for a polished finish, and alcohol eliminates leftover filament dust or build plate adhesive.
For stubborn residue, use a soft brush before alcohol; if you want a glossy look, try acetone vapor (for ABS) or plastic polish after sanding—test on a small area first to avoid issues.