Hitchcocks Forum

As part of replacing my AVL crankshaft timing case oil seal I have removed the middle drain plug to release any oil in the timing case. The outside of the brass gauze filter on the plug was covered in fibres that once I had cleaned them a bit looked like cotton wool. Other than I somehow managed to leave something in the engine when I had it apart (was careful about cleaning) I really can't think what it could be, the oil filter on these is paper so can't be fibres from that.

Any ideas?