One solution that I have found to remove creosote build-up is to throw all of your potato peels and available acorns directly into the fire. The potato peels can be collected and added whenever you have them. Acorns are abundant in autumn. Since I don't appreciate them all over my lawn, I rake them up into an old metal trash can. I add a handful or two a week. It beats spending $16 every month on the expensive store bought creosote buildup removers every month.
Please, don't forget that no matter what, a professional should clean your chimney either in the spring or before you start your first fire in the fall. :}
Source: A senior citizen friend that grew up on a farm in the 1930's.