Answer
Clean sticker residue first. Sand only after it is mostly gone, using 400 or finer.
Why it happens
Adhesive is soft and can smear into the abrasive instead of sanding cleanly.
Recommended grit
Remove residue with cleaning first. Use 400 or finer only after the adhesive is mostly gone.
Wet or dry
Dry for cleanup; wet only when the surface and stage allow it.
Success check
The residue is gone without new scratches or smeared adhesive.
What to do
- Remove as much adhesive as possible with cleaning first.
- Do not sand sticky residue directly.
- Use 400 or finer only after the surface is no longer gummy.
- Replace paper if it loads with adhesive.
Avoid: Do not sand wet, sticky, or gummy adhesive with coarse grit.