Hello Dobry,
It must be a Chinese cash coin, but the picture is too bad to drive further investigation.
The left side displays the mint name. The right side displays the emperor's name (top and bottom characters) and 寶通, which means nearly "currency" (left and right characters).
Since you have direct access to the coin, you may look for the mint name and the emperor's name (which tells the age of the coin) by yourself, if the condition of the coin enables this.
To know the mint name, compare with the Mandchu characters on
this page. Unfortunately it is French, but you can however use the table in the middle of the page.
To know the emperor's name, compare with the Chinese characters on
this Wikipedia page. You have to compare with the "reign name" (4th column).