The rim of the cans had a flaw that cut my lip on the aluminum

Opened a can of keystone light beer and started pouring into glass but beer wasn't pouring out easily so I check to see why and it had a rolled up piece of paper in it. I pulled out unrolled and dried. It was a quest check with items wrote on it such as: water, busch light 12 pk and prices. This had to be put in can before or after filling. So possibly done by a worker. I am glad it wasn't anything dangerous like glass or razors but if someone thought this would be funny I ensure you it was not.