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=3257048.0The 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 suggesting to blurr the public keys in order to prevent any dusting and also for him to keep public keys private and not be exposed.