Please do include a card or tag warning that nut shells are in the pincushion. I had a girl in class one year that almost died because she laid her arms and hands on a table where someone had made a peanut butter sandwich. This didn't happen at school, but we had to ban peanut butter from the entire school, including children's home packed lunches. Granted, her allergy was unusually extreme, but it is not worth the chance with your pincushions!
(I was amazed at the number of parents who were upset because their child could not bring a peanut butter sandwich to school. I know PB is a convenient lunch to pack, but at the risk of a child's life????!!!!!!)