Hey guys, We've had a number of posts regarding proper coin storage and protection. It's widely known that high humidity is bad for long term storage. Well... how dry is dry enough ? I measured % relative humidity and saw values between 41%rh and 48%rh. Thanks to the cigar smoking fad, there are plenty of reasonably priced hygrometers available, including ones which will store min and max values. Also... does the max tolerable %rh vary depending on what metal is involved (Cu / Ni / Ag / Au / Pt) ? I suspect high grade silver proofs might be more sensitive than other coins.
Relative humidity between 30% and 40% is ideal for coins. As RH gets closer to the 50%-60% mark, coins will corrode, especially the high grade proof silver you're talking about and copper since those metals are more reactive.
Are you sure? The really harsh climate for coins is transit from/to bank in brief case and in and out of coin shows. During cold weather METAL is subject to sweat regardless if slabbed,or air tight container. YOU SAY its 90 degrees? well your AC is on high and cold air is blowing on your breif case. I frequent gun shows and see UNREAL effects on handguns. You must Allow metal (coins too) to gradually adjust to change in tempature. Those slabbed coins with spots were most likly caused by tempature change. OT
Interesting perspective. How would one do this? Sometimes I attend coin shows in the summer. It may be a nice 70 degrees inside the show, but I have to go outside to my car where it's 120 degrees. The car ac might cool to 95 by the time I arrive at home, where my ac is set to 67 degrees. In all practicality, how would I acclimate my coins properly? Winter wouldn't be a problem as it's usually in the 70's outside and in, but summer seems a logistical nightmare. Guy~
simply get a remote starter for your car but seriously for all practical purposes please remember for most of these coins when they were firs tminted they were no heaters or ac or cars and they did just fine. do the best and dont worry about the rest
I already have to watch it due to my vintage Martins and Gibsons....except, with the AZ dryness, I add humidity to them. The coins in the safe are fine here. I've been told, if you live in Florida, DONT collect BU copper ???? Salt air???
salt air is really harmful one of my houses is on the sea and i have managed to use intercept shield and temp control to preserve bu copper so its possible to collect bu copper if you have the right protection hope this helps
I would not agree with this at all. You want the air dry as dry as possible. Desired range is well under 10% humidity.
Well i'm talking about a good realistic RH to keep your house at so that its comfortable for you and still good for your coins. Under 30% RH causes very dry skin and eyes and under 10% is constant nose bleeds and extremely dry skin and eyes.
I've had a commercial size Honeywell dehumidifier installed in my basement mainly for my coins and have it set at 30% right now. As the humidity climbs as we get closer to summer I will change the setting accordingly. Its not uncommon for the humidity to reach into the upper 90s here on the hottest days.
Ok I did a little research. Copper is the coin metal that corrodes most easily. It does not even start to show signs of corrosion unless it is in at least 35% relative humidity. So anything under 35% RH should be sufficient. Of course like GDJMSP said, the dryer the better so keep your coins in the lowest RH possibe.
Fair enough. But the humidity of my "coin space" can be much lower than the living space. For instance, put lots of dessicant in a safe.
Humidity isn't a problem where I am most of the year. For at least 9 months, it's well below 10% (no chronic nose bleeding here), but during the summers it hovers around 90% with the monsoon cycles. No problems with storage yet, but I do replace my dessicant packs once a year. Guy~
That is the key - you do not keep your coins in the same space you live in. You keep your coins in a sealed container of some sort, whether that be your safe, a Tupperware container, whatever - you keep the coins inside some small space. And it is the inside of that small space that you keep under 10% RH. The rest of your house is not even affected.
What I do for my coins...and only those that are slabbed, in GSA holders, or in some other protective holder...is place them into 1-gallon ziplock bags with 40 gram packs of reactivating silica gel dissicant. The40 gram packs of silca is enough to protect about 3 cubit feet. The ziplock bags are then placed in a safe, of which I aligned the opening seams with weather stripping you get from a hardware store to keep the safe as airtight as possible. The reason I do this only for slabbed or protected coins is that I fear the ziplock bags may add PVC to raw coins. I'd be interested in hearing additional thoughts or comments on my storage habits.
I keep mine in bank vault, climate control assures vaulables will keep. Also, no threat of muggers breaking in ripping me off while i'm away. A thief can blueprint your home so fast, common for friends of thief to sell blueprints too homes they have visited. NEVER let any-one in your home that you don't know real well. Never reviel location where your safe/valuables are located in your home. Only YOU and your family need to know. Good Luck, OzarkTravler
