Just found this and I think it is pretty interesting. Anyone interested in lapping/polishing heatsinks or improving overall efficiency of MBPs cooling, read on. http://www.overclockers.com/why-heatsink-polishing-might-be-a-bad-idea/ Alternatively, you can read this too: http://forums.pcper.com/showthread.php?441460-Heatsink-Lapping-Guide This second guy says NO to polishing too, but for different reasons. Also he recommends different and much finer grit sands, as opposite to the guy in the first link. I believe this is a good thing to discuss, especially with people who knows better in these areas than average joe. In my point of view, the best would be to smooth/polish the hell out of the heatsink to make the best perfect flat smooth surface you can get and add NO thermal paste at all, just nice contact between two metal surfaces. But I guess it is not really possible to do so in the home amateur environment.