http://thisoldshed.tripod.com/electrolysis.htm
Lots of sites out there detail this but here's one I found.
Parts sat for about 3hrs. They are exhaust clamps and were likely so bad because a) they were near the ground and b) they were very hot every time the bike was used.
Positive clamp was attached to a piece of scrap steel which now looks like it has been submerged in salt water for a few years (looked great before!).
I STRONGLY SUGGEST READING UP ON THIS before attempting it. You are working with electricity in close proximity to water AND creating hydrogen gas.