With the growth in online Auctions, the market is no longer restricted to a few wealthy Irishmen, the world is now your oyster.
In their last Auction, a case of La Mission Haut Brion 1961 was valued €12,000-€16,000 but sold for €29,000 (plus buyers premium, plus VAT!)
But, to get a decent price, you will have to prove provenance and correct storage since first shipped! Harder than you think, unless it's been stored in the one place since purchase.
Or, you could just start drinking them. Less money in the Bank, but more fun!