The comments on engine rejection are in my view fairly accurate. If I find a lump of metal on a chip plug or in an engine filter which is beyond the laid down limits in size I cannot assume it comes from an oil can!!!!
Today there would be 2 options. Getting the metal analysed resulting in loss of use for a few days, expensive, or rejecting the engine even more expensive.
Some engines e.g the Allison 250 have the oil pump before the filter so the metal will have possibly damaged the pump and been distorted so to be no longer recognisable as a can sliver.
Engine failure probably would not result from a can sliver, but the costs of a maintenance rejection could be nearly as high.
A number of years ago an American company supplied a can sized cap which had an opener built in. It opened the can, sealed it and had a strainer built into the spout. The spout had a cap to keep dirt out once the can was opened. I wish I could get a few of these.