What do you mean "a lot of crap around" it? Carbon deposits finding their way to the outside?
If that's the case then you almost certainly want to be changing the gaskets. But you should also be careful as if someone's done the job [badly] before, they might have done the bolts up brutally tight instead of to the correct torque, and twisted the inlet manifold causing it to blow.
You should clean the EGR valve, inlet manifold and ports too. With the ports, you don't want crap going back into the engine - what I do is get the vacuum cleaner hose and hold it near the port, then scrape the crap off carefully with a screwdriver. Use carb/intake cleaner for the EGR valve/manifold, but get as much off as possible while it's dry, as it becomes one hell of a messy job when it's all wet. A big box of nitrile gloves and a large pile of old newspapers are needed.