Cleaned flue for my wood boiler and still had fire!?

I cleaned my flue pipe last am and sometime in the middle of the night had a flue fire. I thought my flue was turning white from over burn but this am I woke up and notice the new pipe parts had turned white again. Not only that but creosote spit from a lower seam all over the top of my wood boiler. Any ideas on why i am getting this creosote so fast?