Discoloration on PEP66 Base

[Nagorak]

I've been using my Alpha PEP66 for a while, and I have noticed that there is some discoloration on the copper base of this heatsink. Does anyone know why the base would become discolored in such a way, and whether this hurts anything. Also, will lapping the bottom cause this discoloration to go away? If not, what will work (or is it not worth the effort of cleaning it up)?

Thanks for any information.

[dimmreaper]

Alphas are forged. If the raw material has any contaminant (dirt, grease, paint, damn near anything) on it when the put it in the die and press it, the contaminant will become permanently embed in the heatsink.

I don't think it will severely effect performance, but it will have a very small effect.