Instructions
Monitor the price of gold over a period of weeks by checking online at sites such as Kitco. Look for an upward trend or a steady level of interest. Don't sell when the trend is downward or the market in gold appears to be volatile.
Locate either a specialist numismatic auction or a general sale with a regular coins section. You can find links to a number of coins auctions at the Coin Resource site. Only place your items with an auction house that attracts the widest possible range of bidders through the use of the Internet and has a track record of achieving good prices for coins. A well-publicized auction will draw both the numismatists and the bullion investors.
Place your coin in the auction along with all relevant documentation such as original proof of purchase, certificates of authenticity and any packaging. The more complete the provenance of the item, the easier the sale. Educated buyers know a good provenance makes it easier for them to sell the coin at a later date. That knowledge will push up the hammer price at the auction.