Here is a (fuzzy, sorry) close up.
This example reads "17 A \". So, what does this mean? (Answer at the bottom of the page)
The following chart shows the canning code symbols with the year each was used.
|1935||A simple "X"|
|1937||The "X" now has both sides closed, forming a "bow-tie"|
|1938||Bow-tie with single dot top/middle|
|1939||Bow-tie with two dots, top/middle and bottom/middle|
|1940||Bow-tie with three dots|
|Beginning in May 1942 beer cans were limited to use by the military. Breweries could use what cans they still had in stock for civilian use. Civilian beer cans did not return until early 1947, so from mid-1942 until late-1946 you should only find these symbols on cans meant for military use.|
|1944||Diamond with a single dot in the middle|
|In 1945 and 1946 two different dating codes were used.|
|1945a||Diamond with one outside dot, top/left|
|1945b||Diamond with one outside dot, top/right.|
|1946a||Diamond with two outside dots, top left and right|
|1947 marks the return of cans available for civilian use. Some civilian use cans have the 1946 code. Presumably they were made ready for civilian canning to resume and filled in 1947.|
|1947||Diamond with three outside dots|
|1948||Diamond with four outside dots|
|1949||standing on its face.|
|1950||Number "7" with inside dot|
|1951 has two different dating codes.|
|1951a||Number "7" with inside diagonal. Looks somewhat like an arrow cursor. I do not see this one very often.|
|1951b||Number "7" with one leg, it resembles the Greek letter Pi. I see this one more often than the previous variation.|
|1952||Greek Pi with two legs|
|1953||Greek Pi symbol with three legs|
The code is 23-A followed by the 1953 code, so this can was made in 1953 at the Baltimore, Maryland facility.
One final note. The symbol is sometimes sloppily printed, so it can be helpful to compare the symbols on more than one example of the same can.
Thanks to Bob Porter for his help.