The value of your Ohio plates depends mainly on the Year of Manufacture regulations of Ohio. Plate collectors look for plates in their original paint, and legible, so condition is everything to a plate collector.. On the other hand if they can be repainted and legally used for antique car registration under the Year of Manufacture regulations of Ohio that is where your best $$$ value would come from. The international club of license plate collectors is alpha.org but do not expect to find appraisal information on this site. (Automobile License Plate Collectors Association). Collectors grade plates as Poor, Fair, Good, Very Good, Excellent and Mint, with sub category that might apply to some of these plates as nrp (needs repaint). The last appraisal guide was published in 2009 although a new price guide is expected to be available in 2016.