SOrsucci, welcome to SMF! Be sure to stop over at Roll Call and say "hi" to everyone. That's where folks look for new members.
A certain amount of buildup in a smoker is good, but it is usually smoke related caked on the top and sides of the smoker from grease that has mixed with the smoke. It helps seal the smoker.
If the smoker hasn't been used in a long time though, it can become loose and start looking flaky, like it is going to fall off onto the meat. If that's the case use a grill brush to scrap off the loose stuff, then rinse it out of the smoker. If there is a greasy looking buildup in the bottom of the smoker's cooking chamber from old fat drippings, go ahead and wash/scrub that out too.
You may get some more ideas here too.
Hope that helps.
Be sure to use the search feature to get some ideas for tasty, smoked chicken.
Have fun!
Ray