I like the copper washer idea. I'm always afraid of stripping the drain plug bolt (I did it on my first bike, but never since), so I avoid the urge to over-tighten. On the other hand, I once read a post from a guy who lost his oil drain plug on a highway on-ramp, sprayed his rear tire with with oil and busted up himself and the bike pretty good. That story makes me want to tighten the crap out of it. Maybe the copper washer would relieve my anxiety.