Last night I did my third oil change on my 04 WR450f. With the aid of my BillyWho, I'm getting pretty damn fast and clean about it. So much that I think I got a little ahead of myself... Once I was all done and putting away my tools, I looked down and I noticed a nice copper washer on the floor where I was changing the oil. I don't recall taking a copper washer off a bolt in previous oil changes, but alas, there it was, with a little oil on it. I looks like its the size of either the frame bolt, or the rear drain bolt, but for some reason, I think it goes on the rear drain bolt. Can anyone confirm? Any risk running without it and putting it back on after my next oil change? I hate to make waste of all that fresh oil. Or am I crazy and this thing is just a sign that I need to clean my workspace better?