Size the open area, airflow path, filter loading, makeup air, and work position with a smoke or tracer test.
Reduce dust attraction without attaching unsafe improvised grounds to isolated plastic or energized equipment.
Refine curved baseboard without flattening beads, sharpening coves, or cutting through adjacent paint.
Separate a shallow finish scuff from cracks, bends, bead-seat damage, machined-face mismatch, and unknown coatings.
Blend a repair on molded ABS without flattening an entire factory texture or assuming primer will recreate it.
Use wet refinement on approved plain rigid PVC without polishing past the paint-preparation endpoint or leaving pale slurry in corners.
Refine a cured polyester casting's rough rim or back without turning its already glossy display face into another polishing job.
Use a full wet-sanding and polishing trial on matching uncoated polycarbonate before committing a noncritical cosmetic part.
Read cured epoxy after rinsing and drying to distinguish scratch refinement from low spots that require a different repair decision.