Depending upon what type of creosote your speaking about. There is basically two types. One is used as a preservative which is a coal tar/oil and the other is the by-product from a fireplace that collects inside the flue.
The coal tar creosote is a liquid that is applied to the wood in which it soaks into the fibers preserving it. So its doubtful you could remove it all as it penetrates the wood.
The latter fireplace by-product can be removed by scraping and sanding the wood until its clean again.
Creosote is a hazard to humans and should not be used for anything other then preventing wood decay. It should not come into contact with water supply as it can easily leach into the water polluting it.