Can a Heatsink go bad?

Hey everybody, I got some heat sinks over here that we were taking a look at. Before I get into it let me tell you the background, we had a laptop come in and it was over heating, we would turn it on and immediately on startup it would hit 100 degrees, we did all the basics reapply the thermal paste make sure it was all ok and still overheating, we came to a conclusion that it was the heatsink, so we go ahead and order a new heatsink and the same thing happened. We did more research and this was apparent with this model and it was a very common problem so we ordered a brand new heatsink, and that one worked perfectly and the pc was not overheating anymore, so we opened up to bad heatsink and we found a weird black residue on the inside, looked like corrosion or something, after opening up other heatsinks and comparing them, we saw that it was faulty, so can a heatsink which is a piece of metal that transfers heat go bad? Yes, it can. And that’s what’s going on today at PC911. PC 911 Computer & Cell Phone Repair http://www.PC911247.com