MacBook Heat Sink Compound

My MacBook Core 2 Duo 2.16Ghz always has 63~65°C in the idle mode (CPU speed at 1.0Ghz and lowest fan speed). After that I disassembled the MacBook, I found there is no much dust around the CPU fan, heat sink. However, I removed the heat sink, I found heat sink compound has already solidified and not uniformly put on both die of the CPU and chipset. Finally I remove the compound and put new one on booth. Now, the CPU temperature in the idle mode drops to 58~61 °C.

The Original Heat Sink Compound