I guess it's just the color combination, the yellow on navy blue colors look very nice together. Jim Fox tells me that, although there was no official city coding in Ohio at this time, a good deal of these "CH" series plates were distributed to motorists in his hometown of Cleveland Heights.
#OHIO LICENSE PLATE STICKER COLORS SERIAL#
This plate was also from Cuyahoga, not surprising in that its serial is only one off from the plate above. This plate was issued in Cuyahoga county, as indicated by the two-alpha prefix (block AA1 through QZ9999 were issued in Cuyahoga). Scarlet on grey issue, honoring the colors of Ohio State University, which was celebrating its 100th anniversary in 1970. This was a New York die variety plate issued in Stark county. By 1970, Ohio's capacity was back to normal and standard Ohio dies were reinstated for all issues.
As a result, a majority of the plates for 1968 and about half of the plates for 1969 were manufactured in New York, using distinctive New York dies of the era. Due to a 1967 fire at the prison's plate shop in Lebanon, Ohio, the state was not up to full manufacturing capacity by 1969. Click here for a complete listing of Ohio county codes. Some municipalities required local tax payments in 1968/69, and a decal such as this was seen on some plates during that time frame. Possible combinations on this base include 12345, ABC, A1B2, ABC1, A12345, AA1234, 12345A, 1234AA, A1234B and probably others that I'm missing. Most Ohio plates of this era were issued in blocks by county, resulting in a multitude of possible combinations.