There was a thread on this issue within the last week or so that you might refer back to however it was about a quilt not blocks. If I recall, several said leaving it outside to air worked (avoiding direct sun fading) and a product from Sam's called Odorout or something like that. Several suggested washing with vinegar. If you just gently soak your blocks in the sink and lay flat to dry you would probably be Ok unless they were not prewashed/preshrunk in which case soaking May change their size..