Looks like the "church keys" we had in the 50's & 60's. I'm sure it could be older than that, however. Ah, how I miss the good old days... No pull tabs back then (but lots of bottle caps).
HH
dts
Well the ones I find underwater have names like Vernor's, Goebel Beer, Coke, and others on them. Yours is so crusty I highly doubt you can find a name on it.
It was called a church key or churchkey and they were invented in 1935. So to date it would be 1935 - around the end of the 1960's
What you found is not a bottle opener "church key", it is a can opener, many church keys had both a can opener and a bottle opener combined, you can tell the different in that your's has a point on it's end, a bottle opener would look much the same but instead have a rounded end.
The type of can opener like your's was designed to punture a hole/s in older style cans to extract the liquid inside, e.g. canned juice, milk, motor oil, and most importantly BEER
, etc., here are some examples of church keys and combination church keys, and one photo showing how the can opener like the one you found would create the hole/s in cans, the combination church key in this photo has a bit different bottle opener then how I discripted them above, there were several different designs for the bottle opener end but the can opener end was much the same on all church keys.
I included a link above to what seems to be known on how the term originated, here it is again.
Though no one seems to know for sure but it seems that the term was used because of the similarities of how the first bottle openers look compared to some keys to unlock Churches.
Church keys were invented around 1898 to open bottles only, the can opener was added to "church keys" much later in 1935 when beer was first introduce/produced in cans.
It would be very hard to say how old it is without finding some markings on it, e.g. brand name, patent number, etc. but it wouldn't be any older than 1935.