I have the valve cover and upper timing belt cover off on my 1998 Honda Accord 4 cylinder (replacing leaking valve cover gasket, etc.). So I have a chance to get a look at the timing belt.

I'm noticing that there's a noticeable amount of brown/red (looks much like rust) dust covering some things in there. I can rub this dust off the sides of the timing belt, and also rub it off of the inside of the camshaft gear. What's up with that? What's it from, and do I need to be worried?