Before you try to sell your old frames, you should attempt to identify them. Antique frames can be quite valuable but make sure that you don't have reproductions. In the 1980s there were many frames made to look old, and I saw one on eBay that I know is a reproduction because I had the very same one.
Collectors want Victorian (or earlier) ornate handmade frames, especially if they are signed by the craftsman who made it. Certain artists created their frames as well as rendering value. Collectors also want frames made that reflected the style of the day, say Eastlake or Art Deco.
Frames should be in perfect condition. Features like gold or silver leaf or iconic decorations are highly desirable. Before you try to sell any item, you should find out what it is. Check out some books to help you:
"Collecting Picture and Photo Frames" from Schiffer Books for Collectors
"Antique American Frames - Identification and Price Guide" by Eli Wilner
"Looking at European Frames - Guide to Terms, Styles, and Techniques" by D. Karraker.
Some of these books are older and information will not reflect current value but will help you learn about old frames. You can then look for more specific values online. Selling them is up to you. You can contact a local dealer who may buy them outright or sell them on consignment. Of course, you will not earn top value as the dealer must make a profit and cover overhead. You can sell them on an online auction site that specializes in antiques and collectibles.