Nope! You don’ have to wash it. Take your pastry cloth off the board and give it a hearty shake outside. I always suggest outside- you don’t want a flour cloud in the house, there’s already enough flour everywhere! So you can then stretch the cloth back over the board and store somewhere cool and dry until next week. If it’s gonna be longer than that, take your freshly shaken cloth, fold a couple times and place into a zip top bag. Toss it in the freezer until your ready again. Tip! Be sure and pull the cloth out of the bag immediately, there could be a bit of frost in the bag.