If you bought your pipe from ebay and the description was good you should already know. But we will determine this now regardless.
-Take a look at the rim. Does it have 'cake' on it? Well if it does (like mine here) it will need to be removed. If it's slightly charred there's only slightly destructive things that can be done to remove it but that's beyond the scope of this instructable.
-Look at the stem. Is it oxidized? Is there a lot of 'tooth chatter' around the bit? There are several materials that a stem can be made out of and the type we'll be dealing with here is Vulcanite. Eseentially hardened rubber. This material will oxidize over time as the sulfur used in the hardening rises to the surface. Lucite, and acrylic stems do not oxidize and are much easier to deal with.
-Can you remove the stem? Gently twist the stem and try and remove it. Don't twist or pull too hard as it's possible to crack/break the shank (the wood the stem fits in to) or break the tenon (the part that fits in to the shank) off which would be no good.
I couldn't take the stem out when I got this pipe so I put it in the freezer for a few minutes and the cooling allowed me to twist and remove the stem.
And now that we know what we need to do let's move on!