You know what is really crazy? We had a 97 Civic with 166725 miles on the odometer, driven by a 52 year old man break down in the middle of Gray Highway in front ot the shop just last week. We thought it just had a broken timing belt, but we pulled the cover off and the cam pulley was lose and spun out. Pulled the rocker arms off and the cam was locked down. The engine was clean on the inside and the oil was not low. We ended up putting another head on it. As far as "trash", it sounds like you saw the aluminum that would have transferred to the cam upon lock up as there is some metal transfer.