To clean it I'd use lighter fluid, this is really good for a deep clean. Use the right stuff though! Then use something like lemon oil to put the moisture back in.
The lighter fluid disolves grease and oil really well, and brings up the wood grain nicely. But it will dry the wood too, so you need to put some oil back in afterwards. Lighter fluid is also very good on some finishes, but test it first! Or ask someone who knows which you can use it on, I'm not certain myself.
