Interesting hydrogen peroxide experiment results

[DirtFlipper]

Howdy,

It's been my experience that soaking Wheats and Indians in hydrogen peroxide (heated or not) darkens them. Looking for an alternative, I tried using Magic Eraser, which is a commercial version of melamine foam (sold by the Mr. Clean folks). (It's not really an 'eraser' per se, but a sponge that has micro fiber like behavior to get into tiny crevices and lift dirt out). For coins that only have dirt on them, it's worked well for me. (Badly encrusted, pitted, corroded - no).

But I thought I'd run a little experiment to sort it out a bit more. I took a 1962 Memorial cent from circulation to be the 'control subject', and two Wheats that were found from the same place, same ground conditions. The 1940 Wheat I just rinsed with water and a toothbrush to knock off the large dirt bits, then soaked both it and the 1962 Mem in peroxide. The 1936 Wheat I cleaned with soap, water, and toothbrush, then used Magic Eraser on it.

The 1962 Memorial cent was completely inert in the peroxide. No bubbles, no fizzing, nothing. The 1940 Wheat fizzed away. Here's a pic of the results of the three of them side by side (order is 1936, 1962, 1940)

[attachment 173139 2010Sep10020.jpg]

As you can see, the 1962 Memorial cent did nothing, while the two Wheats have different shades.

I then thought I'd soak the 1936 Wheat in the peroxide next, to see what would happen to it. Here it is next to the 1962 first for reference:

[attachment 173140 2010Sep10023.jpg]

While soaking, it did fizz a little bit. Here's how it came out:

[attachment 173141 2010Sep10b002.jpg]
[attachment 173142 2010Sep10b003.jpg]

(you can click on the pics for large images)

So at least in this experiment, my Wheats both still darkened. This may suggest that there is still a layer of something that the peroxide is able to remove that the Magic Eraser is not, which results in a darker toning. Don't know why. I still prefer the lighter toning that Magic Eraser leaves, but peroxide is good for certain cases too. (Disclaimer: coins of numismatic value shouldn't be cleaned; leave that to the pros).

HH,
DirtFlipper

 

[captn_se]

Interesting experiment, DF.

I wonder if you were to rub the '36 or '40 wheat with a baking soda paste (baking soda and water) immediately after you take it out of the peroxide, if it would lighten back up? I've never tried it before because I rarely use peroxide. I usually just clean my silver, and run my wheats under warm water to wash the dirt off.

Thanks for sharing!

CAPTN SE
Dan

 

[jimhank]

...The 1962 Memorial cent was completely inert in the peroxide. No bubbles, no fizzing, nothing.
DirtFlipper

A little thing to remember on this. lincoln cents 1909 to 1942 where made of bronze (copper and tin, I think).
After wwll 1943 to 1982 where made copper/zinc alloy (like early IH, pre 1865). Of course 1982 and up are copper plated pure zinc (zincolns).
Seems the peroxide affects the tin in the bronze, but not zinc in the copper/zinc alloys.

 

[captn_se]

From the US Mint website:

The Composition of the Cent

Following is a brief chronology of the metal composition of the cent coin (penny):

* The composition was pure copper from 1793 to 1837.
* From 1837 to 1857, the cent was made of bronze (95 percent copper, and five percent tin and zinc).
* From 1857, the cent was 88 percent copper and 12 percent nickel, giving the coin a whitish appearance.
* The cent was again bronze (95 percent copper, and five percent tin and zinc) from 1864 to 1962.
(Note: In 1943, the coin's composition was changed to zinc-coated steel. This change was only for the year 1943 and was due to the critical use of copper for the war effort. However, a limited number of copper pennies were minted that year. You can read more about the rare, collectible 1943 copper penny in "What's So Special about the 1943 Copper Penny.")
* In 1962, the cent's tin content, which was quite small, was removed. That made the metal composition of the cent 95 percent copper and 5 percent zinc.
* The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc). Cents of both compositions appeared in that year.

Possibly, the reason why the '62 cent didn't fizzle, or darken, was because of the slightly different composition (no tin) of the coin.

HH,
CAPTN SE
Dan

 

[dewcon4414]

Along with the different composition ... the time spend in various conditions of the soil, water, and salt will change any metal. Look at those zincs after say 50 years or even in high salt soil. That darking may be coming from the salt.... either way dark is not a desirable tone id like my coins to have. Nor is the kind of purple that many will turn if other chemicals are used. I dig the eraser.

Dew

 

[DirtFlipper]

Ok, so to explore a bit further, I tried a 1936 Wheat that I got in change from McDonald's last year (I think I did better eating a cheeseburger than hunting that day as I recall, hmmm...).

Here's the before:
[attachment 173212 2010Sep11013.jpg]

And here's the after:
[attachment 173213 2010Sep11016.jpg]

I think Abe got a little bit of a tan, but not too much. There was a little faint effervescence. Not the effect I get on recovered Wheats, but perhaps just a slight hint.

So being in the ground seems to play a factor.

HH,
DirtFlipper

 

[jimhank]

(Note: In 1943, the coin's composition was changed to zinc-coated steel.

Oopps, I thought the steels where '42. But thats right...the "copper" war penny ('43). I forgot.:blush: