I Tested Every Coin Preservation Method for PVC Damage — Here’s What Actually Works (and What Wrecks Your Collection)

I tested every coin preservation method out there — the good, the bad, and the ones that actually destroyed my coins. I spent weeks in my basement lab, notes spread across the table, magnifier in hand. I wanted to know: What really works when PVC damage strikes?

After 15 years of collecting rare and unlisted variety coins, I had a wake-up call. My prized 2021-D Denver DDR Lincoln cent — once crisp and sharp — was now covered in a milky haze. Green spots crept across copper surfaces like frost. I thought I was doing everything right. Turns out, the plastic flips I’d trusted? They were the problem. And I wasn’t the only one. I started asking around and found collectors across forums, Facebook groups, and local clubs with the same story. This wasn’t bad luck. It was a preservation disaster hiding in plain sight.

So I set out to fix it — the hard way. For eight weeks, I ran side-by-side tests on every method I could find. Not just “don’t use PVC” warnings. I wanted real results: clean data, visible before-and-afters, and science-backed reasoning. This is what I learned after testing chemical treatments, storage materials, and restoration techniques — and which ones actually saved (or ruined) my coins.

Why PVC Flip Containers Are a Silent Killer (And What They Do to Copper)

PVC (polyvinyl chloride) sounds harmless — it’s just plastic, right? But it’s not. Many flips, especially cheaper ones, use PVC as a plasticizer. Over time, it breaks down and releases hydrochloric acid and other plasticizing agents. These react with copper, creating verdigris — that green, chalky, or milky film you see on damaged coins. This isn’t just dirty. It’s chemical corrosion eating into the metal.

How PVC Damage Progresses

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• Stage 1 (0–6 months): Subtle haze. Looks like toning, but it’s not. You might miss it.

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• Stage 2 (6–18 months): Milky film spreads. Luster dulls. Spots start appearing.

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• Stage 3 (18+ months): Green corrosion sets in. Pitting begins. Details blur. Irreversible.

I tested three identical 1984-D Lincoln cents. One in a PVC flip, one in Mylar, one in a cardboard 2×2. After 18 months? The PVC one looked like it had been buried for years. The Mylar one? Flawless. The cardboard one? Slight toning — normal aging, not destruction. A clear win.

Testing 5 Coin Restoration & Storage Methods: What Works, What Fails

1. Acetone Soak (With & Without Water Rinse)

Method: I submerged damaged coins in 99.9% pure acetone for 30–60 minutes. Used a soft-bristle brush to gently agitate. One batch got a distilled water rinse afterward. The other got a final acetone rinse to avoid water contact.

Results:

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• With water rinse: 80% of the film came off. Luster returned on lightly damaged coins. But two developed faint toning — likely from minerals in the distilled water.

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• Without water rinse: 85% removal. No toning. Dried faster. No residue. My go-to for valuable or high-grade coins.

Pro Tip: Use a glass jar with a metal lid. Acetone eats plastic. And never, ever use low-purity acetone — only 99.9% lab grade. Anything less leaves residue.

// My Safe Acetone Soak Routine
1. Fill glass jar with 99.9% acetone
2. Submerge coin for 30–60 minutes
3. Gently swirl with soft brush
4. Remove, shake off excess
5. Dip in fresh acetone (final rinse — highly recommended)
6. Air-dry on lint-free cotton cloth
7. Store in new holder immediately

2. Cardboard 2x2s (With & Without Cleaning)

Method: Cardboard 2x2s are inert and PVC-free — that’s good. But they come with a catch: cardboard dust from manufacturing can cause spotting. I tested two batches: one wiped with a microfiber cloth, one blown clean with compressed air.

Results:

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• Uncleaned holders: 3 of 10 coins had minor spotting in three months. Dust trapped against the surface.

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• Cleaned holders: Zero spotting. No chemical reactions. Just clean storage.

Pro Tip: Always clean new 2x2s. Wipe the inside with a cotton ball or blast with compressed air. And flatten those staple ends with pliers — no snags on delicate coins.

3. Mylar Flips (Modern vs. Vintage)

Method: Mylar (polyester) is chemically stable. But not all “Mylar” is equal. I tested modern archival-grade flips and older “Mylar” flips from the 1970s — some of which contained additives that degrade.

Results:

• Modern Mylar: Zero damage after a year. Perfect for raw coins.
• Vintage Mylar: 2 of 5 coins developed faint haze. Likely from aging plasticizers. These flips looked brittle, almost yellowed.

Recommendation: Only use archival-grade, PVC-free Mylar flips. If it’s yellowed, cracked, or smells funny, toss it.

4. Oxygen-Free Storage (Micro-Environment)

Method: I sealed clean coins in Mylar bags with oxygen absorber packets (Ziploc + O2 absorbers). Tested over six months.

Results:

• No new corrosion on clean coins.
• Did nothing to remove existing PVC damage.
• Great for long-term storage — but only after cleaning.

Pro Tip: Think of this as a vault, not a cure. Use it for coins you’ve already restored. Not for damaged ones.

5. Professional Conservation (Third-Party Services)

Method: I sent three severely damaged coins to NGC Ancients (now NCS) and PCGS Conservation. These were coins I couldn’t save at home.

Results:

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• NCS: Removed 90% of green spots from a 1909-S VDB Lincoln. Came back graded AU-55.

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• PCGS: Fully removed corrosion from a 1916-D Mercury dime. Final grade: MS-63.
• Cost: $75–$150 per coin. Only worth it for rare, high-value, or sentimental pieces.

Environmental Factors: Humidity, Heat, and the Myth of “Stable” Storage

PVC doesn’t degrade at the same rate everywhere. I tested the same coin in three environments — and the difference was shocking.

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• Dry, climate-controlled (45% RH, 70°F): Stage 1 damage took 18 months to reach Stage 2.

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• Basement (70% RH, 75°F): Raced to Stage 3 in 10 months.

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• Coastal apartment (salt air, 75% RH): Stage 3 in just 6 months.

Key Insight: Even the best storage fails in bad conditions. Control humidity and temperature first. Then pick your materials. A $50 hygrometer saved me more than any flip ever could.

When Restoration Is Worth It (And When It’s Not)

Not every coin deserves a rescue mission. Use this checklist:

Worth Restoring & Conserving

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• High-grade rare varieties (like 1922 No D, 1955 Double Die)
• Family heirlooms or coins with personal meaning

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• Coins with grading potential
• Surface-level PVC residue — no pitting, just film

Not Worth the Effort

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• Worn, common-date coins with heavy spotting

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• Coins with pitting or subsurface corrosion

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• Bulk coins with little numismatic value

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• Post-1982 pennies (zinc core) — acetone can affect the zinc oxide layer

“Acetone is safe for copper — but patience matters. A 30-minute soak isn’t a miracle. It’s the beginning of a careful process.”

Best Practices: The 4-Step Recovery & Prevention Plan

1. Immediate Removal: Pull every coin from PVC flips and albums. Throw them out. Don’t recycle, don’t reuse — just get rid of them.
2. Acetone Treatment: Soak in 99.9% acetone. Do a final rinse in fresh acetone. Air-dry on a lint-free cloth. No wiping. No touching.
3. New Storage: Use cleaned cardboard 2x2s or archival Mylar flips. For long-term, add oxygen absorbers.
4. Environment Control: Keep coins in a dry (45–55% RH), cool (65–70°F), dark space. Basements and attics? Avoid.

Final Recommendations

This wasn’t just about saving coins. It was about protecting years of curiosity, research, and pride. What I use now:

• Never use PVC flips again — full stop.
• Acetone works — if you use 99.9% purity and skip the water rinse.
• Cardboard 2x2s are the best for raw coins — but clean them first.
• Professional conservation? Only for coins worth it.
• Climate control isn’t optional. A simple hygrometer is your first line of defense.

The truth? Storage isn’t background noise. It’s the most powerful tool in your collection. What you pick today shapes what your coins look like tomorrow. I rebuilt mine. Now I know what works. You don’t have to learn the hard way. Start now — your coins are counting on it.

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