For the last end grain cutting board I made, I used Wenge, Maple, Jatoba and Marblewood. I finished it with 5 coats of butcher block oil. Now, when the board is wiped with a damp cloth after use, some of the wood coloring appears on the cloth. This is the first time I have come across this phenomenon. Anyone have any thoughts? Of course, there were no stains used so what is coming off is from the wood. Not sure how or why or how to prevent that in the future.