I would not wash them before they are assembled, you could end up with a knotted mess. Put either a baking soda "refrigerator box" , a few pieces of charcoal wrapped in newspaper, or a handful of silica packs (those little packs that come in a box of new shoes) in the bin and close it back up for a couple of days. This will remove the odor and not harm the fabric or blocks. I'd love to see pictures of these treasures.