If you’re buying wine as an investment, you’ve got to buy the best wines in full cases, in the original wood cases and from only the best vintages. Keep these for the future; in a cellar with a consistent temperature for ten years or more then sell them for a huge profit. You’ll have return on your investment; have proved what a confident seller you are but will you have any satisfaction? – Alternatively, you could buy twice as much; selling off half and then technically having the other half for yourself for free.
If you want to sell to a wine merchant; they won’t want your junk, but they’re often short on older wines and are happy to make a deal if it’s god stuff and in good condition.
If your cellar is beginning to overflow, you can start to sell off anything that no longer suits your taste, standard of collection, a loss of interest in an area or to make room for a new interest.
Web sites such as Wine Bid and Wine Commune have made selling wine even easier. Both offer online auctions, registration is free and they’re very intuitive sites with tons of information, postings about wines, etc. They take a sellers commission of between 12 to 20 percent, depending on volume and have very accurate, detailed accounting reports.