PVC (polyvinyl chloride) damage occurs when coins are stored in soft plastic flips, binders, or holders containing this chemical. The PVC breaks down over time, releasing a slightly acidic reaction that can harm the metal of the coin. This reaction can cause residual deposits to appear on the coin’s surface, [says The Spruce Crafts].
PVC damage typically manifests as greenish, milky, or gray streaks or haze. In more severe cases, it can appear as small green blobs or a shiny green layer covering the coin’s surface.
Copper and bronze coins are particularly susceptible to PVC damage, followed by silver, gold, and platinum. Even valuable coins can have their value significantly reduced or even destroyed by this damage.
- Avoid Soft, Flexible Plastics: As a general rule, the softer and more pliable a plastic coin flip is, the more PVC it likely contains. Hard, stiff, and brittle flips, often made of materials like Mylar, are a safer choice.
- Opt for PVC-Free Storage: Look for coin holders labeled “PVC-free” or made from archival quality materials like polypropylene, polyester (Mylar), or polyethylene. [NGC] uses acetate flips for submissions.
- Consider Hard Plastic Holders: For high-value coins, hard plastic holders, sometimes referred to as “slabs” by professional grading services, offer robust protection.
- Store in a Stable Environment: Regardless of the holder type, coins should be stored in a stable, dry environment to prevent tarnishing and accelerate degradation.
Yes, in its early stages, PVC residue is removable. Acetone is a commonly used solvent to dissolve PVC residue. However, the process requires care and proper ventilation, as acetone is a volatile and flammable compound. If the PVC has corroded the coin’s surface, the damage may be permanent.
It is important to remember that cleaning coins can impact their numismatic value, especially for rare or collectible pieces. If you are unsure how to proceed, consider consulting with a professional conservator or coin grading service.
Does PVC plastic damage coins?
As it degrades, PVC will become yellow, cloudy and brittle, off-gassing acids into the storage environment. This may lead to a green, sometimes sticky residue on coins, with possible permanent staining and corrosion making the coin’s value reduce considerably.
What does PVC damage look like?
I can help with that. PVC damage appears as greenish, milky, or grey streaks or haze. In severe cases, it looks like tiny green blobs on the surface of the coin. It can significantly damage your coin’s surface if you’re not careful!
Does vinyl damage coins?
From my experience, Is there safe vinyl? No. All such “coin safe” vinyls, although they have little plasticizer, still will release hydrogen chloride over time. For this reason, no form of vinyl is approved by museums for preserving collectibles.