I changed the oil today in my motorcycle, and over on the left is a picture of my drain plug. It has a magnet on the end of it, so all those little hairs you see sticking out are metal particles that stuck to it. This is stuff that wasn't caught by the oil filter. It makes me glad to have that magnet in there!
The amount of material probably isn't unusual since a lot of this debris likely comes from the clutch; fortunately, cars don't have oil-bathed clutches like most motorcycles do, so they don't have to worry as much.
It'll be interesting to see how well the highly-touted Shell Rotella T 5W-40 oil held up for almost 4,000 miles. I think a lot of folks will be surprised by the amount of viscosity shear, although I expect its TBN to hold up fairly well. And, no, I'm not bashing the Rotella—it is a fine motor oil. It's just that most folks don't realize that most motor oils rapidly shear out of grade when subjected to the shearing action from the transmission and they end up running their oil way too long. This will cause damage to the transmission gears and it'll promote the formation of sludge in the engine as all those VI improvers break down.
Oh well, out with the old and in with the new... oil, that is. My bike is now filled up with Redline 10W-40 and a dose of Lube Control 20. We'll see how far this combination can go before shearing out of grade or becoming too polluted with insolubles.