As an early Casascius buyer/holder I viewed these coins as nice memorabilia items and didnt think of getting Chain of custody for future authentication.
Obviously with the high value these coins have now it's becoming something both seller and buyer want assurance on.
So if a seller doesnt have chain of custody would the next best solution be to have the coins in question checked by trusted experts? Eg: Hologram, coin pressing, ink used etc.
Suggestions for other methods to authenticate?
Post some photos here with the public key blurred if need be. We can take a look at the coin and hologram and let you know.
Also read this thread. https://bitcointalk.org/index.php?topic=3257048.0
The printing for the public key is another authentication mechanism so blurring it will make authenticating it less certain. Things like ink pigment and bleeding under magnification should be consistent with your control(known good coins). The early coins that were inkjet printed right onto the hologram should also match. As time goes on these aspects of the coin will age and a newer copy would stand out.
That is true and good point. I was asking to blurr to prevent any dusting and also for him to keep pub key private and not be exposed.
I've yet to see a compelling argument that dusting is harmful. I have even sought out dusted coins for their historical significance like the Sochi Olympics duster. Not that I would but you can exclude the dust when you redeem it.
I like my Cas coins to be pure at 1btc
But to each his own.