To Clean or Not to Clean: The #1 Rule of Coin Care

The Golden Rule: Never Clean Your Coins

This is the single most important rule in numismatics: never clean your coins. Cleaning removes the original surface — the natural toning, luster, and patina that developed over decades or centuries. Once removed, it cannot be restored.

How Cleaning Destroys Value

• A cleaned Morgan dollar in "AU" condition might look shiny, but PCGS/NGC will assign a "Details — Cleaned" grade, which sells for 30–60% less than a naturally toned AU coin.
• Cleaning creates microscopic scratches (hairlines) that are permanent and visible under magnification.
• Chemical cleaning (dipping in acid solutions) strips the surface layer, making the coin appear unnaturally bright.

Recognizing Cleaned Coins

• Unnatural brightness — Especially on older coins that should have some patina.
• Hairlines — Parallel scratches from wiping, visible under angled light.
• Dull, washed-out appearance — Lacking the natural "glow" of original luster.
• Mismatched surfaces — One side cleaned, the other natural.

The Only Exceptions

• Professional conservation — PCGS and NGC offer conservation services that can safely remove PVC residue, environmental deposits, or light surface contamination without damaging the coin.
• Acetone soak — Pure acetone (not nail polish remover) can safely remove adhesive residue and PVC without affecting the coin's surface. Soak only; never rub.

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