Can coins be damaged from moderate heat?

109* is not enough to melt a coin but it may warp the plastic if it’s sealed in such. You’re concerned about coins left in your mailbox. Where is your mailbox located? In the shade, in full sun? It doesn’t take much imagination to see the difference. A metal mailbox in the sun acts like an oven. So is your mailbox metal or plastic? In short the heat can damage the coins in other ways without melting them.

 

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I didn’t address the heat issue because 12 other members did.

I responded to your admitted ignorance to a known abrasive to coins…and everyone on the street who answers no to toothpaste harming coins is wrong…

…and I will never buy one from anyone if I know it has been treated with toothpaste…imo…Spark

 

Here is an example that I bought this way. Either by accident left on the dash in the summer or some other reason, all the coins are cameo and have no hazing. Would be interested if anyone has a TPG slab example. I dont think this could happen in a shipping package. Seems to me it would need to be in direct sun for a while.

 

A zincoln maybe, but 109 temperature would not affect a copper coin, not hot enough. Unless like stated above, the coin packaging and other factors are present. Good question, thanks.

 

Yes, elevated temperatures can damage your coins and the holders in which they reside and what happens to the holder can have an effect upon the coin.

First: Obviously temperatures in the 110's and up can warp plastics, particularly if they have been constructed with residual, unrelieved stresses.

Second: Almost all plastic materials outgas some of their chemical constituents. Think of what your new car smells like when you open the closed door on a hot day. That odor is almost entirely comprised of the chemicals in the carpet, fabric, vinyl and foam that makes up your car's interior. And if you left the remains of a cheeseburger in there, that too. And these materials outgas faster and more voluminously in higher temperatures.

Third: Corrosion for most common metals doubles with every 10 degree F rise above ambient temperature (~68F). So, if there is some corrosion on your coin, no matter how slight, then raising the temperature will accelerate that corrosion rate. And remember that all toning and haze on a coin is just corrosion.

Fourth: Mix accelerated corrosion from temperature with outgassed chemicals from holders and the mix might range anywhere from benign to toxic for your coins.

Conclusion: As a general rule, you should not subject your coins, no matter how they are housed, to extremes of temperature and humidity for any length of time. Unfortunately, no one can tell you what the boundary conditions might be so you just have to judge conservatively.

 

Strawman. he did not "admit" any such issue. What he asks is a valid question. Very valid. A tongue in cheek example used to emphasize the question is just that, and emphasizes the questioned concern.

Using strawman is in itself ignorant and dismissive, in my opinion.

 

And lets not forget using erasers. My brother did this to all of his wheat cents until I caught on and warned him off. Back in the 60's of course.

 

I believe the temperature has to be well above 265 degrees and have a stress factor to cause deformation of acrylics type plastic. It is only 113 today , nice breeze. If I can find a "sample" PCGS slab from a convention, I will do the experiment, but I think I gave them away for club prizes. Jim

 

I know that used to happen and that really proves the point though. Anyone around back then stopped doing it because it was damaging the coins. Anyone who started after that in the last several decades was taught never to do that. While it may be fine for polishing the silverware, anyone that knows anything about coins would know not to use it on them

 

There are other issues that can cause an issue with the coin. As to temperature, the outside temperature 95? After one hour a closed condition auto is 140. Outside temp 110? After 2 hours inside auto 155.

All metals react to the surroundings. There will certainly be a reaction between the holder and the coin in excess heat conditions, and would have some effect, I would think.

The TPGs have discussed this issue on their websites, as I recall. I think years ago the recommendation was 75 degrees storage, but I don't remember any outside temperature recommendations, other than caution against very large swings.

 

I think perhaps you misunderstood the toothpaste reference.

 

She made a reference saying toothpaste does not harm silver or gold and that is not true…Spark

 

How would you know, for certain toothpaste was the cause?? Is it possible that it may be ignorance if you don't know?

 

Not so. She chose an awkward analogy and perhaps didn't convey it with clarity. See post #15.

 

@Maxfli …my post #14 was a injection of clarity, an attempt to counter thoughts about toothpaste used on silver, gold or coins in general. Several members have agreed with my corrective instruction…imo…Spark

 

Clarity can not be injected. Your conveyance of thought is an example of awkward analogy.

So:
"....an attempt to counter thoughts...".

Is and was a failed attempt. I don't know if I would consider the attempt ignorant, but.......it may be.

What is a worthwhile attempt to be ignorant, is stating "....several members have agreed with my corrective instruction....", under the guise of applying a deliberately false nuance to an innocent use of a metaphor, and knowingly doing so to belittle another member.

Accordingly, I decided to emulate your gracious attempt at corrective instruction.

(I think my emulation attempt was pretty good...insert smiley face here).

 

@Gam3rBlake …apparently another member @charley thinks I belittled you, and if I did I apologize because that was not my intent. I just thought you had an errant notion about toothpaste…imo…Spark

 

@Spark1951, ignore Charlie. He reads posts and injects his own meaning to them and then picks flame wars over it. He’s a troll.