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Safe Coin Storage...aka. No, Virginia, slabs are not airtight

Post anything about coin grading holders, questions, images, facts announcements. If it's in, or about, or is a coin holders this is where to post it.

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Safe Coin Storage...aka. No, Virginia, slabs are not airtight

#1 Unread post by Earle42 »

I do not believe there is any claim by any grading company that their slabs are airtight. That idea is, like so many other things, an assumption made by the masses.

When stored, coins degrade primarily from both exposure to air and humidity. The chemicals in the air oxidize (yup ...just like a nail rusting!) the metals and change their colors.

Since degradation/oxidation and tarnish are ugly words, we are blessed with marketers who have succeeded in getting the word "toned" used instead.

Any cardboard in an album's construction (sorry...even Dancso albums) will help oxidize coins. The cardboard surrounding the edges of the coin absorbs humidity/atmospheric chemicals and react with your coins...specifically if in MS condition (mostly non-chemically reacted surfaces).

Removal from humidity and air is essential for maintaining an MS surface.
1. Move to Arizona where there is so little humidity (which helps maintain chemicals in the air as well).
2. Use holders that do not allow air circulation.
3. Also store coins in a closed container with a desiccant (silica gel packs).

Best non-cardboard solution:
1. 2X2 holders ... Yup! The old cheapie standby. When stapled inside the NON-PVC versions (likely hard to buy anything but this nowadays) are not perfectly airtight, but there likely is not going to be enough air that will be flowing over the coin's surfaces while trapped between the two plastic sheets to make much of a difference. Caution: always pliers-flatten the back of installed staples! The "bumps" made by staplers are well know for ripping the plastic off of the 2X2 below it when you stack 2X2s. Or simply get a flat clinch stapler.

2a. Use coin capsules, such as Air Tite brand, which fit almost perfectly the dimensions of your coin. These capsules are likely not actually airtight either...but logically when you enclose something inside a tightly closed system with no wiggle room, air is going to have a hard time getting inside and circulating well.

But capsules are a pain to store!
They make tubes for this. I personally have used old multiple row boxes designed to store 35mm camera slides (& include a large packet of silica gel inside).


2b. Combine the above capsules with a brand of album known as Encap coin albums. These are albums molded to hold the the capsules your coins are in.
You can buy the sheets (eBay!) separately and they fit any 3-ring binder.

But the capsules and albums cost a lot more than 2X2s!


So get creative:
Bad and old picture 1948-1982
Bad and old picture 1948-1982
Three pieces of sign-shop-left-over plexiglass scraps. Careful (!!) drilling performed with spade bit.

Those have been inside that case since 1982. Almost forty trips around the sun, w/out being stored correctly a lot of that time (basement - humid - I was younger), and no tarnish/degradation/damage (oops) toning!

3. Honorable mention. Ever see those food vacuum storing systems that use bags? I store some coins in a vacuum sealed bags such as rolls of old pennies. The bags will eventually lose vacuum, yet I have gone three years (possibly more, I opened the bag) with with the vacuum being there! Psst...put the first vacuum sealed bag within another one. Plastic bags are inexpensive!

My vacuum source back then was inexpensive. My Mcdonald's milkshake lent me its straw when it was through (with) it. Straw in bag, seal all but where straw is in, inhale and pull straw out of bag while pinching shut that small area of bag.

I graduated to a large syringe and aquarium hosing next.

Then the day came...I saw a used food vacuum storage system for 3.00 at a Goodwill store. Needed cleaning though.

Summary - find some way to get as airtight a storage system as you can. Use a desiccant such as gel packets.

Oops - and you thought this book was done.

Gel packs. Local furniture stores pay for garbage to hauled away. This includes many gel packs shipped to them with every piece of furniture. Get friendly. Ask them to hang a Walmart bag up in the back room where they unbox things. I got a lifetime supply in one month and the landfill thanked me.
Fact Check the grading Companies:
Fact checking grading company shortcomings on NO FG halves: or higher resolution version:

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Re: Safe Coin Storage...aka. No, Virginia, slabs are not airtight

#2 Unread post by Daniel »

Good posts.

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