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While I save whatever nickels I get in pocket change, I do not go out of my way to get rolls to hoard. When I want to hold onto metals, I don't want anything with more than 10% "impurity."

• Silver eagles with .999 silver? Great.
• Copper pennies with .95 copper? Yes.
• Gold eagles with .917 gold? Sure, if I can afford it.
• Junk silver with .9 silver? OK.
• Nickels with .75 copper? Sorry, just too low.
• 1965-70 Halves with .4 silver? No thanks.

If I do wind up with anything below 90% purity, I'll trade them in for something else when the time is right.

Am I missing something with the CuNi hoarding? Some of this mixing is done for stabilization and durability, but I still hold at my 10% limit. I would think it's a lot easier to pass something as slightly impure than as a mixture, especially if one day we actually need these coins as sources of metal for manufacturing. I'm often tempted to cash in my nickels at the bank and get more pennies to sort.

The value of CuNi is not in the separating of the alloy as I see it.

75/25 CuNi is a very valuable alloy just buy itself used for many purposes in manufacturing, and it seems handy to have it stored in 5 gram increments.

From the wiki:
Cupronickel or copper-nickel is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Cupronickel is highly resistant to corrosion in seawater, because its electrode potential is adjusted to be neutral with regard to seawater. Because of this, it is used for piping, heat exchangers and condensers in seawater systems, as well as marine hardware, and sometimes for the propellers, crankshafts and hulls of premium tugboats, fishing boats and other working boats.

A more familiar common use is in silver-coloured modern circulation coins. A typical mix is 75% copper, 25% nickel, and a trace amount of manganese. In the past, true silver coins were debased with cupronickel. Despite high copper content, cupronickel is silver in colour.

Thermocouples and resistors whose resistance is stable across changes in temperature contain the 55% copper-45% nickel alloy constantan.

Monel metal is a nickel-copper alloy, containing a minimum of 63% nickel.

Copper nickels are commonly specified in heat exchanger or condenser tubes in evaporators of desalination plants, process industry plants, air cooling zones of thermal power plants, high-pressure feed water heaters, and sea water piping in ships.[9] The composition of the alloys can vary from 90% Cu–10% Ni to 70% Cu–30% Ni.

Single-core thermocouple cables use a single conductor pair of thermocouple conductors such as iron-constantan, copper constantan or nickel-chromium/nickel-aluminium. These have the heating element of constantan or nickel-chromium alloy within a sheath of copper, cupronickel or stainless steel.[10]

Beginning around the turn of the 20th century, bullet jackets were commonly made from this material. It was soon replaced with gilding metal to reduce metal fouling in the bore.

Currently, cupronickel remains the basic material for silver-plated cutlery. It is commonly used for mechanical and electrical equipment, medical equipment, zippers, jewelry items, and as material for strings for string instruments.

For high-quality cylinder locks and locking systems, the cylinder cores are made from wear-resistant cupronickel.

If you can't get the money in other ways and you have the time, machinery, or inclination to sort pennies then cash in the nickels. Otherwise I think the 75% copper/ 25% nickel US nickels are a good hold. The 25% nickel in it is still worth something. I got a few boxes of nickels and I will hold them unless I got really desperate for money. The ease of acquiring them and the fact that it is no risk makes it attractive for me, and I just like nickels. The nickel will be debased by the government at some point. It is just a question of when.

Otherwise less than 90% metal coins don't bother me as long as there is a market in which to sell them that is available. I mostly do the higher purity coins but have some 10%-80% silver coins which can be easily sold.

.999 Canadian Nickel can satisfy your needs of pure nickel

There is no ban, easy sell, and liquid. Also .999 purity is more enjoyed by manufacturers that actually require .999 pure nickel or can create their own alloys after buying .999 (such as 90% Ni/10% Cu, 60% Ni/40% Cu, etc.

Thanks, Kurr. That's the info I was missing.

The purity doesn't make much difference so long as either a) the metals can be separated without much fuss, or b) it is a valued alloy.
Cupro-nickel has many uses. And so does brass.
It's when you get into more exotic mixtures or unknown mixtures that you could run into trouble.
If you have two metals that cannot be easily separated that's a problem unless it's a commonly used alloy.

Robarons wrote:.999 Canadian Nickel can satisfy your needs of pure nickel

There is no ban, easy sell, and liquid. Also .999 purity is more enjoyed by manufacturers that actually require .999 pure nickel or can create their own alloys after buying .999 (such as 90% Ni/10% Cu, 60% Ni/40% Cu, etc.

That's why I like to pick some up whenever I can!