I think most folks don't go to the trouble to seperate them. I toss mine in buckets that I call my "Sub-Prime" copper. One member here pollishes them up in a rock polisher and then overstikes them as beautiful new copper bullion pieces.
If your percentages are low.. just sort more. If your percentages are high.. just sort more.
Now selling Copper pennies. 1.6x plus shipping. Limited amounts available.
I never clean a coin except for dropping the worst of the sticky/gunkified pennies in a jar of isopropyl rubbing alcohol to make them a bit more pleasant to handle. I figure (hope) my children or grand children will be sorting through my Cu hoard after I'm gone (unless Cu really makes a big run in the near future). There will at least be lots of shiners that will make fine collections. When they find the ones that have numismatic value, I'm hoping to not have ruined it by cleaning the coin.
I had been wondering about very dirty/gunky coins...does the Ryedale have trouble with them? Is there a way to clean them up a bit before you machine sort them or do those of you with Ryedales just toss them in and then clean your machines later?
It's funny how the Wheats I find look pretty clean and legible (especially for their age and amount of time in circulation), then the copper LMCs look mostly cleanish and relatively easy to read their dates but the worst looking pennies are usually zincers and 9 times out of 10 efforts to degunk the grungiest pennies to date them means they're the least valuable of all the pennies to put the effort into :(
My Ryedale does not jam on the ugly pennies but it does jam on the really bent coins and on every UK penny it finds. All pennies are a little dirty so you need to occasionally clean the machine up, but the Ryedale includes a bit of a self cleaning feature on the hopper. I definately do not clean pennies before processing them. That would be WAY too much work.
Oh and to answer the original question - tarnished pennies are just about as good as the rest of the copper pennies and they all go in the same bucket for me. The Ryedale sees through the tarnish and even green pennies. I toss the REALLY ugly ones back into circulation but then I'm pulling 50% copper so I can afford to toss the odd penny back.
“The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.” – George Bernard Shaw. Why Copper Bullion ~~~ Interview with Silver Bullion Producer Market Harmony Passive Income blog