A friend has his Mooney 201 in for annual. When the mechanic inspected the oil filter he found what is in the picture. No other metal and it is magnetic. He pulled the sump and did not find anything. They will continue looking next week. Anyone have any ideas where this came from? The engine has 1600 hours and I believe it has not been into since last overhaul. To me, in the picture, it looks like it broke off the right side. I asked the owner if it is flat on the side laying on the paper towel and he did not know. Dowel????