Yes, you do need to wrap them for a couple reasons. First, the soap will draw moisture out of the air , get sticky & stick to the paper if you don't & second, the soap will wither, shrink & crack over time, you will see a difference in a couple months. You can use a cheap thin brand of saran wrap & wrap it snug in that before you slip the band on. You can still smell through the saran. It is harder to smell through the cello or shrink wrap & I think the shrink wrap leaves an odor on the soap. Shrink on CP is OK because you leave the ends open for the bar to breath, but sealed tight I smell a distinct unpleasant odor.