Air filter - clean or replace?

[downeypiglet]

Hi guys. So as much as I can tell my GZ has had a diaphragm failure of the petcock. I am going to replace the petcock, oil filter, spark plug and obviously do an oil change. The questions I have are: do I need to replace the (stock) air filter, or just clean it; and is there anything else I need to do to additionally? The bike has been sitting for a few months and I'm just now getting around to dealing with this. Do I need to clean the tank and / or carb?