If you're crazy for cranberry glass or a fiend over Fenton, deciding how to find out what your treasures are worth may keep you awake at night. Collectors tend to be passionate about the items they love, and those who appreciate old glass are no exception. You can narrow down the value of old glass by consulting experts and doing your own hands-on research.
Look It Up
Check out a few volumes on collectible glassware from the library, or look them up online. Numerous books on the subject have been published, and they can be as generic or as specific as you like. Kovel's is a reputable name in the collectible glassware field. They publish both printed and online guides to help you find the value of pottery, porcelain and almost every manufacturer of old glass on the secondhand market. The most important thing to remember when using books as guides is to check the publishing date. If your book is old, your prices will be too.
Watch and Learn
As your grandfather could probably attest, you learn a lot by visiting the local estate sales in your community. If you haunt them frequently enough, you'll begin to get a feel for what collectible glass is currently bringing. Whether it's Indiana or carnival glass, cobalt or ruby, you'll eventually run across it at an estate sale. This is a good resource for gleaning the value of other types of collectible glassware as well -- the glass that's popular, but not yet highly valuable, including advertising glassware like the type given away as promos at fast food establishments, old soda bottles and vintage canning jars.
Antique shops are valuable resources for finding out how much your old hobnail milk glass goblet is worth. But keep in mind that when you're pricing an item in an antique shop, the price you're seeing is likely top dollar. If you plan to sell your items online in an auction setting, at a garage sale or by word of mouth, the price you can get may vary a bit from what someone is willing to pay for the same item at an antique shop.
Whether you take your old piece of Depression glass to a local appraiser or visit "Antiques Roadshow" for your estimation, having something appraised by an expert gives you the most clearly defined price range. An appraiser will take into account the era from which the glassware hails, the manufacturer, the condition of the piece and its rarity -- whether it one piece of a limited set or mass produced. All of these factors have an impact on the value of old glassware.