Replacing Heatsink/fan on Processor

[Doomsayer]

Hello,  my friend has just gotten a new fan/heatsink for his P4 processor  (Socket LGA 775)   and i offered to install it for him,   i have done this before and am familliar with the process,  but i have not "replaced" an already existing fan/heatsink   so i wasn't sure what to do about the leftover heatspreading substance on the processor.  should i carefully clean it,  and with what, or should i just put the other one on there,   notting that the new one has it's own fresh layer of the stuff.  
thanks for your help.

Doomsayer

[soybean]

Use a razorblade or other fine edged instrument to carefully remove most of the old thermal pad/compound. Then, soak a paper towl or cloth with some rubbing alcohol and carefully wipe the remaining compound off.

[Doomsayer]

hey,  thanks for the quick reply,  just one more thing,   should i remove the processor or just leave it in the mobo?

[soybean]

I believe the best procedure is to remove the processor for cleaning.  Be carefull not to bend the pins on it.  Here's one reference on Replace a CPU's Heatsink and Fan which advises removing the processor.

[Doomsayer]

thanks a lot for your help soybean,  i greatly appreciate it.  

Doomsayer