A miki with the clasp and the box and/or the original documents is saleable on eBay. If you have never sold on eBay- there is a bit of a learning curve to it, but in the case of documented mikis, it will be worth it. I never saw one go for cheap; they have a way for finding their market value- because of the box, docs, and clasps-
Check out some of the eBay Miki auctions we have discussed on this forum. There is a whole forum for pearls on eBay. And there are several Miki items. Also. go to eBay and type in Mikimoto pearls, whatever is being sold now, if anything, will show up.
YOu will need good photos of the strands, the clasp and the documents to get the best price on ebay. You are welcome to post your pictures over here for advice on the starting price, etc, if you think you would like that.