Attaching second heatsink to Athlon

[nemouk]

I have a spare heatsink lying around and i want to attach it to the back of my "Classic" Athlon.

What would be the best method, bearing in mind that i will most likely be selling this chip in the future and i may want to take the heatsink off.

 

[Bakwetu]

Putting back on the plastic casing? I doubt that would be very effective. It's better to just remove the plastic casing, which can be done without damaging it too much.