Can I reuse heatsink from a Socket 473 P4 rated to 3.4 GHz to a Socket 939 Athlon 64 X2?

It is a used aftermarket copper heatsink, I know heatsinks can reused on same grade CPUs, what was the one cleaning out used and harden thermal paste?
Update: Oh that Athlon 64 X2 is dual-core rated 3800+ 2.0 GHz.
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