1st a little background info. I have an 05 Focus ST w/ the 2.3l Duratec engine. At 5000 miles I filled the crankcase w/M1 5W20, but at 10000 I switched back to MC 5W20 because I just couldn't see spending the extra money on the M1 when I have to change the oil at 5K intervals to comply w/ my warranty. At 15000 I changed the the oil and it seemed like no problem. Here's where my concern lies. As I was pouring the from my drain pan into the bottle to take it back for recycling I noticed some little stringy thing inside the oil flow as it went out of the drain pan. Im my mind I'm thinking that must be contamination from the drain pan (I don't do a world class job of cleaning it after each oil change) but after a little time passed this began to bother me. What are the chances that this was some kind of sludge contaminating my oil? Thanks for any responses.