A couple of them weren't in very good condition after going through the wash but that was ok, I just cut some fabric out around the damage and sewed up the sachets. I bought a set of fine sewing machine needles especially for the task and promptly misplaced them. I had an inkling that for such a light-weight fabric I should alter the tension of the presser foot pressure or some such but, well, I was too lazy to look it up. So I just sewed - no problems.
Now each closet and cupboard with woollens therein also has a lavender sachet and (I hope) no moths.