no real reason to worry about it. It is not a "dirty" part. You would not crack open your exhaust system to clean them out. I would only clean it if you had it out or replacing it for some other reason.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)