There are 2 ways to go about selling your bottles: The first is to find a good auction house like Christie's or Bohams (if it's a good bottle), and have it appraised for auction.
(Usually they will waive the appraisal fees if you place your bottle at auction with them, but expect that most auction houses will take a 20-30% cut of the final price.)
The other way to sell your bottles, is to contact an independant Vintage Spirits Appraiser that also handles private sale: Independant VSA's often have a large resource of
contacts that may be interested in your bottles, and you will often get a better "end price" for the bottles this way, as you are not having to pay high auction house fees to
attract buyers to you - Instead the VSA will take your bottle to known buyers that will offer you the best prices, which is usually on par with current auction results.
***Independant VSA's can work for either the buyer or the seller, and usually work on a 10-15% commission. (The commission being paid by whomever the client is.)
I'll drop you a private message, and help you find a good VSA in your area that handles private sales also!
Walter C Hurst