ya that is like most zippos then, you should be abe to remove the metal casing from the outer shell where you should see a foam pad inside. Buy rosinal (sp) lighter fluid and then fill the sponge until it is fully damp but not overflowing so that it doesn't cover the lighter. The put the outer shell and inner shell back together and take some type of cloth or towel to wipe down the zippo removing any excess lighter fluid. It should work perfectly after that and you will have to refill zippos fairly frequently depending on their use and if they are not used for a prolonged period of time the sponge will naturally dry out on its own.
Depending on the zippo their should also be excess wick inside the body of the zippo so after a while you may have to take a set of needle nose pliers and pull the wick further up if it has begun to deteriorate.
Hope this helps and check out zippos tricks online so much fun!
T "It's my storm. I can make it do whatever I want."