Plastic cutting boards are more sanitary since they can be easily disinfected with cleaning agents and hot water. Wooden cutting boards can hide bacteria and germs in the grains of the wood.
A knotting board is used for holding macrame while it is being made. A cutting board is used as a backing for rotory cutters used in sewing and especially in quilting.
First give it a good wash and scrub in hot soapy water, rinse it well and dry it, leave it somewhere warm to 'air dry' for at least an hour, then sprinkle one side with bicarbonate of soda, and leave...