Waltham pocket watches have been around for more than 150 years and are a collector's item. They were made between 1851 and 1957 in Waltham, Massachusetts. Like any other collector's items, the oldest and rarest pieces are the most valuable, so it is important to know as much information as you can about a watch before buying or selling it. It is fairly simple to confirm a watch is a Waltham pocket watch and to identify the model and manufacturing date.
Identify the type of pocket watch. There are three basic types. A hunting case pocket watch has a closed case that goes over the face of the watch. An open face pocket watch has no cover over the face and it winds at the 12 o'clock position. A sidewinder pocket watch has no cover over the face and it winds at 3 o'clock.
Open the back cover of the watch with your fingernail and look for identifying names -- a magnifying glass or loupe may be necessary. A Waltham pocket watch will have "A.W.W.Co." and "Waltham, Mass." on the movement, which is the inner workings of the pocket watch. This will also include the grade of the watch. For instance, a Riverside grade watch will have "A.W.W.Co. Riverside Waltham, Mass." on the movement.
Write down the serial number. This is also on the movement and can be used to date the watch.
Look up production dates online, on sites like Oldwatch.com. Corresponding years and serial numbers will be listed. If the serial number is between two dates, it was made in the earlier date.
If your watch has a cover, look on the inside. "AWco" written on the inside of the cover means the cover was also made by Waltham. A "K" with a number means the case is made of gold, and the number indicates how many carats it is. For instance, "K18" means the case is made out of 18-carat gold.
If "adjusted" is on the movement on the back of the watch, that means the watch has been adjusted to keep time in various conditions, which adds value to the watch.
If your watch case is difficult to open with your fingernail, do not force it open or pry it open with a knife, you could easily damage the case or the crystal. Take it to a jeweller.