Can you still use a polishing board to polish a walnut string that is disk red?

Yes. Walnut strings after playing for a period of time, polishing plate polishing is possible, but re-polishing is equal to the original pulp all off, have to re-play for a period of time will be out of the pulp, give up or not give up to think about it and then make a decision. Walnut string is a wood product, it is now very popular among people's favorite wooden play.