So if the fuzz-- stuck to the magnetic plug, - it is magnetic. -- thereby ruling out aluminum, copper and other things that are not -magnetic.
this could be iron from the block, ring material. -- i agree with the cutting open of the filter and reviewing what else is swimming around.
you can also send a sample of the
oil to someone like blackstone labs to see exactly what it is. -- there is a certain amount of fuzz that is expected in a new engine up to about 1200 miles, and it should drop off to nothing.