This is why you may want to get an XRF analyzer if you're buying material from the cheapest supplier in those quantities. For the rest of us, it's ad-hoc tests: CCA wire melts with a match flame, CCS gets attracted to a magnet, for CCC there's no obvious test, and if you can find legit copper conductor stockpile it now.
Having said that, if you read the original discussion, https://news.ycombinator.com/item?id=47304934, it looks like he brought this upon himself.
