Date stamped into coin

I have a New Brunswick 1 cent coin that has a date (and some letters) stamped onto the obverse and reverse, as though it were "cashed in" or otherwise taken out of circulation. The coin is either from 1861 or 1864 - I can't tell because the stamping obliterated the last two digits.

The obverse is stamped
F
N S
16

And the reverse is stamped
MAY
25
1886

Has anyone seen a coin like that? What is the history behind stamping a coin in such a way?

I can take some photos tonight if anyone is interested.

Thanks,
Jesse

Pictures would be nice....

Here's a scan.

I'm thinking New Foundland Society or something. 16 being the person's number within the group and a special event that occurred on the date.

It was a Tuesday...a Ugandan was speared...(other useless information I found!)