Just type in the exact marking you are looking for. For example...Hemingray, Brookfield, etc., or look at the list of common error markings at the bottom of this page and try a few of those.

Searching by CD, U, or M number will probably not find the "hidden" insulator. It will most likely lead you to a knowledgeable collector's insulator. Which can be a good thing too!

Search for typos from the seller. Consider these: Insalater, Inslator, HEMINGWAY, BROOK FIELD, WHITAH TATUM, etc...

Search the seller's descriptions of the markings: glass dot, backwards 7, backwards N, raised lettering, etc...

Don't limit yourself to searching only the insulator category. It is useful to look into sections other than insulators. For example, I have found insulators listed in the following categories: Bottles, Jars, Collectibles, Hobbies, Transportation, Telegraph, Railroad, Americana, Folk Art, Glass, Art, Ceramics, Pottery, Crafts, Candles, Candle Holders, Historical Memorabilia, Decorative Collectibles, Advertising, Lamps, Militaria, Tools, Hardware, Housewares, Radio, Telephone, Tools, Gardening, Home Decor, Oddities, Miscellaneous, Weird Stuff, etc...

Imagine that you are a seller that knows nothing about insulators. Which words would you use to describe this weird hunk of glass you are trying to sell? Hunk of glass? Hmm... knob, pottery, paperweight, doorstop, globe, decoration, etc... Try some of these words also: Telephone pole, resistor, transformer, conductor,... You never know.

Here are some free search boxes to eBay and uBid. No doubt the best auction sites on the web. Try out some of the keywords. Doesn't cost a thing to look. But if you find that thing you can't live without, remember to bid smart and buyer beware.