Collecting skeleton keys is becoming more popular, which is having a twofold affect: more people are aware of this antique collecting niche, and prices are going up as interests in these vintage keys also increases. As with anything antique, the value of a skeleton key is determined by collector interest, rarity, age and beauty.
Skeleton key values, while on the rise, are still low enough to allow even a casual collector into the game. While a single key can sell for as much as $1,000, most keys usually sell for less than $10 and many go for $1 or less when sold in bulk, according to Genie Taylor of G. Taylor Antique Keys. But as interest in keys increases, fewer will be on the market, and prices are expected to rise. Prices for most keys are kept down because there are so many of these keys around. Most houses built before the 1950s used skeleton keys for nearly every door.
Typically, the more ornate or old a skeleton key is, the more rare, and thus, the more value it will have. Some keys dating back to the 1700s or earlier will have more value. One problem in determining value and rarity is that so little is known about this collectible. Even those people who have been collecting for years are still learning about this niche. The term "rare" is often used arbitrarily on websites selling the keys, but whether the keys are actually rare or simply unknown to the seller is difficult to determine.
Determining the age of a key can be a tricky matter and it's best to consult a guide, according to Taylor. However, the best guides are only available in French or German, giving collectors another obstacle in determining their key's age and value. One resource available in English is "Keys – Their History and Collection” by Eric Monk, published by Shire Publications. To a casual collector, determining age is a matter of the key's style, bit cut (teeth) and general feel of the key. Experts can tell how old a key is simply by looking at the key and the way it was made. A replica of an old key will feel light, be made of aluminum and often have a painted surface. Older keys have a nice patina, which shows their age. .
Because collecting skeleton keys is a relatively unusual hobby, true collectors can find real treasures for almost nothing. That's because so many people may not know what they have in their hands and sell it at an extremely low cost. Auction sites are filled with bulk lots of skeleton keys, and hidden in some of these could be a real find. Collectors who know their stuff can find bargains from the unsuspecting people who have rare keys on hand but know little of their value. With single keys selling in the hundreds of dollars, taking the time to know what you have is well worth it.
Many skeleton key experts discourage people from buying large lots of keys on the chance that one will open an old door or cabinet in their house. However, other than collecting keys, people have come up with interesting uses for the keys, including turning them into unique necklaces and pins, as decorative items or using them as part of artistic creations.