How do I remove a Copper slug from a heatsink?

[or-ex]

I have an old 478 Pentium 4 heatsink, and it has a beautiful copper cylinder in it, so how do I remove it?

I may want to use it for some type of bootleg dice pot..lol

 

[treefrog07]

Put it in the freezer for few hours and see if the Cu and Al contract enough for you to remove the Cu insert.