Some like Sol Noctis have a somewhat convoluted process to redeem, but the process is known.
THERE might be some other coins that for whatever reason have not been discussed on the forum that also have some odd tricks that you have to do to redeem them. We don't know what we don't know. And if there are some oddball collectables out there that have not wound up here then you might have an issue. Stick to the known coin makers if possible.
-Dave
Agree the known coin makers best practice. If anyone has anything to share about makers private keys please post on this thread as well as it is dedicated strictly for coinmakers private keys!.... https://bitcointalksearch.org/topic/--5505467