Protection from humidity

stevepk

Is a glass jar with a packet of silica gel an ideal way of protecting coins in a humid environment? If so, is there any advice? If not, why is this not ideal and what is the best way to protect coins against humidity?

Mr_Spud

That’s a great way to protect coins. I’ve been doing that for years. I use this method for coins in rolls as well as raw coins in Mylar flips. I recently bought some of these jar lids so I don’t have to use humidity indicating cards.

Mr_Spud

Unused empty paint cans from Home Depot work great too. I’ve used both the paint cans and jars for decades to make tarnish proof time capsules to store coins. I started doing that after reading this part of this book. It’s an old, but great, out of print book written in 1964. I first got that book as a photocopy that I borrowed from the old ANA library, but much more recently found a mint state copy of it on eBay for about $10.00

PerryHall

A Tupperware type container or plastic zip-lock bag also works. Include a silica gel pack in each container. Get the kind with the moisture indicator so you know when they need to be recharged in your oven.

Mr_Spud

I use the Tupperware with desiccant to store albums in to slow down the tarnishing/toning so they won’t go terminal. It works great. I live near the ocean and the salty humid air makes everything corrode quickly

lilolme

In the past I have used something like those mentioned above. I bought one of these later. It has some colored beads for moisture content detection. Instructions for when to 'bake' out the moisture. That is a typical screw top lid and one can empty the beads onto a baking pan or can do it within the can. I keep the can sitting on the card with the instructions so I can find it.

Mr_Spud

I’ve been mainly using these rechargeable desiccant packs over the years, 1 per jar or paint can, 3 or 4 for Tupperware. I put these in my safety deposit box too at the bank where I store my slabbed coins. I use intercept shield slab boxes there too in addition to the desiccant since the deposit boxes aren’t airtight. I usually change out the desiccant packs about once every year or 2 and recharge the ones that were in the safety deposit boxes. One time when I didn’t visit the safety deposit box for over 5 years, many of the intercept slab boxes had yellowed on the outside and turned black on the inside. I replaced them all with new boxes and don’t plan on waiting that long to change out the desiccant packs again.

Mr_Spud

I also do similar things at work in my lab with mason jars and large glass desiccant chambers to study the effects of different relative humidities on Softgel capsules with different gel formulas because that’s what I do for a living, formulate softgels. Only there I use different saturated salt solutions that equilibrate to different humidities rather than regular silica desiccants, but the ones with lithium chloride would work great cause that salt equilibrates the atmosphere in the jars to 11.3% RH 🌝

gumby1234

I've used Tupperware and stored coins in a humid basement with no problems.

MetroD

@Mr_Spud said:
I’ve been mainly using these rechargeable desiccant packs over the years, 1 per jar or paint can, 3 or 4 for Tupperware. I put these in my safety deposit box too at the bank where I store my slabbed coins. I use intercept shield slab boxes there too in addition to the desiccant since the deposit boxes aren’t airtight. I usually change out the desiccant packs about once every year or 2 and recharge the ones that were in the safety deposit boxes. One time when I didn’t visit the safety deposit box for over 5 years, many of the intercept slab boxes had yellowed on the outside and turned black on the inside. I replaced them all with new boxes and don’t plan on waiting that long to change out the desiccant packs again.

I have had good luck storing inside of these Intercept bags.

Based on your profession, you are undoubtedly more knowledgable than me on the subject. That said, I am attempting to create a low humidity micro-climate.

Mr_Spud

I like those intercept bags too, but I never used them and went with the intercept slab boxes instead. I think, as long as people do something to slow down possible corrosion on their coins then they are doing something good. If they see any problems developing they can take further steps. For example, I have a bunch of albums, Dansco, Whitman, intercept Shield for the blast white sets, Library of Coins, Meghrig and Wayte Raymond. After moving to California I noticed some of the coins in one of the albums were developing black spots and a couple others started showing signs of mildew on their covers. Even one that was an Intercept Album started showing signs of toning on the dimes that were in it. I didn’t have that same problem with my albums when I lived in Charlotte, but here in California 6 blocks from the ocean, i started having the problems. So that’s when I started putting the albums in Tupperware with Desiccant. I also put the older Meghrig, Wayte Raymond and Library of Coins in a different Tupperware container than the others since the older cardboard is more reactive than the newer albums. I also rubbed the covers of the ones showing mildew with mineral oil and let it soak in and repeated it until they stopped soaking it all in. These were the older albums and the mineral oil worked and the mildew went away and the covers ended up looking brand new.

ricko

@Mr_Spud ... I have one of those excellent 'Coin Preservation' books also. Picked it up years ago on an ebay auction - low price, no competition. Great condition as well. I use desiccant bags in my safe, large ones. And small ones in the cabinets. Humidity is not a huge problem here, just a couple of short periods each year. Cheers, RickO

Mr_Spud

It’s a great book. I looked over on eBay and there’s still some available for $10

MetroD

@Mr_Spud said:
I like those intercept bags too, but I never used them and went with the intercept slab boxes instead. I think, as long as people do something to slow down possible corrosion on their coins then they are doing something good. [...]

Apologies for not being more clear.

For my SDB 'slabs/coins', I use Intercept boxes too. Then I place the box into an Intercept zip lock bag, along with a desiccant pack.

Have not done a 'deep dive' into the permeability of the bags. So, I cannot definitively state that there is an incremental benefit. That said, I have not experienced any issues like yellowing boxes, or discolored Intercept, over a comparable time frame.

It is probably overkill, but I do not believe that it is 'hurting' anything.

Thanks for your suggestions in this thread.

Mr_Spud

@MetroD said:

@Mr_Spud said:
I like those intercept bags too, but I never used them and went with the intercept slab boxes instead. I think, as long as people do something to slow down possible corrosion on their coins then they are doing something good. [...]

Apologies for not being more clear.

For my SDB 'slabs/coins', I use Intercept boxes too. Then I place the box into an Intercept zip lock bag, along with a desiccant pack.

Have not done a 'deep dive' into the permeability of the bags. So, I cannot definitively state that there is an incremental benefit. That said, I have not experienced any issues like yellowing boxes, or discolored Intercept, over a comparable time frame.

It is probably overkill, but I do not believe that it is 'hurting' anything.

Thanks for your suggestions in this thread.

I see, that’s actually a great idea

Cranium_Basher73

Rule of thumb for desiccant/paper humidity indicators:
Blue's cool, pink stinks!

Stingray63

I too use desiccant bags in my safe and pay attention to the temp in the home. Humidity has not been an issue with the way my A/C has been on. Not sure about the glass jars but if doing so would probably recommend only mason jars. Plus keeping in a cooler part of your home and out of constant light.