People usually don’t put scratches into flatbed scanner glass on purpose; they’re usually caused by rough cleaning, dragging gritty debris across the surface, pressing hard with a sharp or hard object, or repeated use that wears the glass over time. In scanner communities, the common advice is to avoid abrasives and fillers, since they often make the damage worse rather than better.

Common causes

  • Dust or grit trapped under a cloth, book, or original document.
  • Using paper towels, rough fabric, or abrasive cleaners.
  • Scraping labels, tape residue, or adhesive off the glass.
  • Slamming the lid or pressing hard on thick items.
  • General wear from repeated handling and cleaning over time.

What people usually do instead

  • Clean gently with a microfiber cloth and a scanner-safe cleaner.
  • Replace the glass if the scratch affects scans.
  • In some cases, users have replaced the glass themselves, though that can be tricky and replacement may be more practical than repair.

Practical takeaway

If you’re seeing scratches in a scanner bed, the safest assumption is accidental damage from cleaning or handling, not something “put in” intentionally. For scanning quality, the usual fix is replacement rather than polishing, especially for deeper scratches.

TL;DR: Most scanner glass scratches come from abrasive cleaning, grit, hard objects, or pressure, and the usual fix is careful cleaning or replacing the glass.