We have both a permanent and a study collection. Permanent collection objects are accessioned and are not provided for hands-on use. As additional gifts are offered, we often allocate duplicate or damaged items to the study collection. This collection is for loans to low security sites like public and university libraries, etc. We also loan these objects for hands-on activities in schools, science fairs, etc. The items are not formally accessioed (however, they are given via deed of gift). I mark each piece with tiny letters in ink, "STUDY." When an item in this collection is broken or damaged from use, it is discarded. Amazingly, few items get damaged so our study collection continues to grow. Hope this is helpful. John Handley