Answer
For light tool rust, use 220 or 320, then refine with 400 or 600 and protect the metal after sanding.
Why it happens
Rust needs mechanical removal, then finer grits to reduce scratch marks on the tool surface.
Recommended grit
Use 220 or 320 for surface rust, then 400 or 600 for smoother finish.
Wet or dry
Dry for rust removal; wet can be used at finer stages after loose rust is gone.
Success check
Loose rust is removed and the surface has an even scratch pattern.
What to do
- Wipe loose dirt from the tool.
- Remove rust with 220 or 320.
- Refine with 400 or 600.
- Clean and protect the metal after sanding.
Avoid: Do not use very coarse grit on precision surfaces unless heavy rust requires it.