Thanks for your question.

It needs to be taken into account that I don't know yet where a possible buyer might be located or which banks there might be situated. Nevertheless, I would ask for something like safety deposit box in a bank where the buyer is located. Buyer could see the coin in advance. if the buyer is satisfied, s/he should transfer the money to seller via the same bank and then the ownership of the coin would change to the buyer.

Something like that. Never done anything like that before but could be worth finding out.

Luckily got to answer your question quickly.

Unfortunately I have to apologize that immediate answer might not be always the case. Sometimes it can be that I can't reply even the same day. I try though my best to check in frequently.