How do I remove creosote from mortar near a clean-out on my hearth?

ChimneyRx Paint N Peel Fireplace Cleaner will clean "carbon-based" stains from masonry and may require more than one application. ChimneyRx Creosote Remover will also be a good recommendation because with the excessive wood burning, creosote will continue to develop. If you can get a handle on the creosote before build-up occurs, this will help tremendously.