You can remove both the burr and all other parts like washer, crank and spring. But please do not detach the screws of the burr set since they have been adjusted in a optimal way for the grinding gear.
To keep your grinder clean you can wash the burr with lukewarm water and/or use a small piece of absorbent cotton or a cotton bud. Do not put the grinder into the dishwasher – it is NOT DISHWASHER SAFE. Do not soak or wash the wooden part with water! Be sure that the burr is completely dried before putting the grinder together again.