# Defective pennies? **URL:** \ **Category:** Factual Questions\ **Created:** [December 8, 2000, 3:54am UTC](https://boards.straightdope.com/t/defective-pennies/44577 "2000-12-08T03:54:40Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [December 8, 2000, 3:54am UTC](https://boards.straightdope.com/t/defective-pennies/44577/1 "2000-12-08T03:54:40Z")
I have, sitting on my desk next to the keyboard, a penny which seems to have had it’s copper coating rubbed off. A lady in front of me at the coffee shop gave it to a cashier, who almost mistook it for a dime because it’s so light in color. I “bought” it from the cashier (ie, I gave her another penny in exchange for it), and kept it to take a better look. It’s dated 1995, so it’s not a WW2-era steel penny. The coin does have a very faint copper color to it, but it’s so faint that you’re likely to see it as a silver coin if you only take a quick look. Was 1995 a bad year for pennies? Can anyone explain what happened to this coin? ---
**Author:** ![galyean](https://avatars.discourse-cdn.com/v4/letter/g/f9ae1b/32.png) [@galyean](https://boards.straightdope.com/u/galyean)\ **Post date:** [December 8, 2000, 4:05am UTC](https://boards.straightdope.com/t/defective-pennies/44577/2 "2000-12-08T04:05:21Z")
Maybe someone was trying their hand at electroplating??? ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [December 8, 2000, 4:25am UTC](https://boards.straightdope.com/t/defective-pennies/44577/3 "2000-12-08T04:25:28Z")
Pennies are not solid copper. They are zinc, which is cheap, coated with a small amount of copper. The copper, through amazingly heavy use for a penny, has worn off, revealing the silv’ry zinc 'neath (I feel anachronistic this nacht). That penny in your hand is worth a lot less than one penny if you were to estimate the value of the materials it is made of. ---
**Author:** ![Dark\_Lord\_Davidson](https://avatars.discourse-cdn.com/v4/letter/d/bc8723/32.png) [@Dark\_Lord\_Davidson](https://boards.straightdope.com/u/Dark_Lord_Davidson)\ **Post date:** [December 8, 2000, 4:36am UTC](https://boards.straightdope.com/t/defective-pennies/44577/4 "2000-12-08T04:36:34Z")
Actually, it’s one of my butt-pennies. Fecal enzymes destroyed the copper coating. I’ll shut up now. ---
**Author:** ![justwannano](https://avatars.discourse-cdn.com/v4/letter/j/7ab992/32.png) [@justwannano](https://boards.straightdope.com/u/justwannano)\ **Post date:** [December 8, 2000, 4:49am UTC](https://boards.straightdope.com/t/defective-pennies/44577/5 "2000-12-08T04:49:45Z")
Could have mercury on it. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [December 8, 2000, 4:56am UTC](https://boards.straightdope.com/t/defective-pennies/44577/6 "2000-12-08T04:56:54Z")
Is mercury that corrosive? I know it kills brain cells and other nerve tissue, but I didn’t know that it could act on other metals. And besides, what person who works around mercury would handle it carelessly enough to spill it on change? ---
**Author:** ![Gunslinger](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@Gunslinger](https://boards.straightdope.com/u/Gunslinger)\ **Post date:** [December 8, 2000, 5:16am UTC](https://boards.straightdope.com/t/defective-pennies/44577/7 "2000-12-08T05:16:45Z")
Dunno about copper/zinc, but mercury is sho’ 'nuff bad for aluminum. You can’t carry a mercury thermometer on a plane, because if it spills, they have to scrap the airframe. ---
**Author:** ![Surgoshan](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Surgoshan](https://boards.straightdope.com/u/Surgoshan)\ **Post date:** [December 8, 2000, 7:25am UTC](https://boards.straightdope.com/t/defective-pennies/44577/8 "2000-12-08T07:25:09Z")
I know that if mercury comes into contact with gold it’ll immediately and nearly irrevocably amalgamate, turning a pretty gold watch into an ugly toxic watch. More likely than not someone has tried to electroplate the penny, or they dipped it in hydrochloric or sulfuric acid (acids will eat away the copper, but not the zinc, I believe). Or the penny has seen some really heavy use. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [December 8, 2000, 8:01am UTC](https://boards.straightdope.com/t/defective-pennies/44577/9 "2000-12-08T08:01:47Z")
Thirding the mercury theory. It used to be a common trick to dip a penny in mercury, and it would look like you had a silver penny. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [December 8, 2000, 1:31pm UTC](https://boards.straightdope.com/t/defective-pennies/44577/10 "2000-12-08T13:31:42Z")
On the flip side (and I only mention this because it’s cool), if you hold a penny in the flame of a gas stove, the inner zinc part will melt before the outer copper coating. You’ll end up with a wrinkled penny. ---
**Author:** ![wring](https://avatars.discourse-cdn.com/v4/letter/w/838e76/32.png) [@wring](https://boards.straightdope.com/u/wring)\ **Post date:** [December 8, 2000, 1:46pm UTC](https://boards.straightdope.com/t/defective-pennies/44577/11 "2000-12-08T13:46:12Z")
Damn I need to get my eyes checked. I thought the OP was something about defective penises. [emily] nevermind [/emily] ---
**Author:** ![scratch1300](https://avatars.discourse-cdn.com/v4/letter/s/dfb087/32.png) [@scratch1300](https://boards.straightdope.com/u/scratch1300)\ **Post date:** [December 8, 2000, 2:30pm UTC](https://boards.straightdope.com/t/defective-pennies/44577/12 "2000-12-08T14:30:30Z")
Someone could’ve put the penny in a tumbler. I did this to a handful of coins when I worked at the sunglasses factory and the penny lost practically all of its copper plating. **Smeghead** , I’m interested in what you said about dipping a penny in mercury. I have a penny (around 1973, so it’s not the zinc-plated kind) that is shiny and silvery and slightly attracted by a magnet. I thought maybe it was a cent struck on a foreign planchet – the U.S. mint will produce coins on contract for other countries, and sometimes a foreign coin blank will remain in the bin and get mixed up with our native coinage. Does anyone know if a U.S. cent dipped in mercury would be attracted to a magnet like this? ---
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [December 8, 2000, 4:48pm UTC](https://boards.straightdope.com/t/defective-pennies/44577/13 "2000-12-08T16:48:26Z")
A coin would need to have significant amounts of iron or nickel in order to be attracted to a magnet. Just to further clarify things: the back of the penny has alot more copper on it than the front, but still not as much as a normal penny. It doesn’t look like the result of heavy usage (although I’m not an expert on that). ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [December 9, 2000, 4:18am UTC](https://boards.straightdope.com/t/defective-pennies/44577/14 "2000-12-09T04:18:20Z")
> [@](#): > > I have a penny (around 1973, so it’s not the zinc-plated kind) that is shiny and silvery and slightly attracted by a magnet The operative word here is “slightly”. What do you mean slightly? It is either picked up by a good magnet, or it isn’t. Slightly just doesn’t compute. **diceman** My educated guess–you have a **cent** that just didn’t get the copper bonded correctly on the obverse (front). Unless someone did play with it after it left the mint. ---
**Author:** ![scratch1300](https://avatars.discourse-cdn.com/v4/letter/s/dfb087/32.png) [@scratch1300](https://boards.straightdope.com/u/scratch1300)\ **Post date:** [December 9, 2000, 1:51pm UTC](https://boards.straightdope.com/t/defective-pennies/44577/15 "2000-12-09T13:51:59Z")
> [@](#): > > \*Originally posted by samclem \* > \*\* > > > [@](#): > > > > I have a penny (around 1973, so it’s not the zinc-plated kind) that is shiny and silvery and slightly attracted by a magnet > > The operative word here is “slightly”. What do you mean slightly? It is either picked up by a good magnet, or it isn’t. Slightly just doesn’t compute. > > \*\* Okay. It _will_ be picked up by a good magnet, but not picked up by a bad one. I hope this clears things up. ---
**Author:** ![Sterra](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@Sterra](https://boards.straightdope.com/u/Sterra)\ **Post date:** [December 9, 2000, 4:13pm UTC](https://boards.straightdope.com/t/defective-pennies/44577/16 "2000-12-09T16:13:02Z")
If you hold the penny to a torch sometimes it will shoot out green flame as its melting.🙂 ---
**Author:** ![anya\_marie](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@anya\_marie](https://boards.straightdope.com/u/anya_marie)\ **Post date:** [December 10, 2000, 12:28pm UTC](https://boards.straightdope.com/t/defective-pennies/44577/17 "2000-12-10T12:28:29Z")
Derleth is right. Pennies made after 1983 are approximately 95% zinc and 5% copper. Apparently copper is too expensive for pennies now, and the silver coins stopped being made 1964.