Need Help With Chinese Cash Coin That Is Overstruck?

Here is an R.O.C. 10 cash that appears to have had some meddling involved in the alloy mixture. The coin actually looks much more yellow in person, but the flash diminishes the brassy look.
Anyhow, the coin looks mostly like brass, but has streaks of copper color through out. There are also some thin peeling laminations, which seem to be more common for brass coins like this.






Then there is a Hupeh 10 cash struck over Korea 5 fun. Note that the die used is a contemporary counterfeit one and does not match any official dies.





Finally, a Szechuan 100 cash struck over Hunan 20 cash. This one seems to be an official piece, struck as part of the period of re-evaluation of the cash currency.

That was sold way too high in my opinion. But again, supply has diminished for some reason.