Quotation for Shabbat 245:13

A needle whose eye or point is missing is clean. If he adapted it to be a stretching-pin it is susceptible to impurity. A pack-needle whose eye was missing is still susceptible to impurity since one writes with it. If its point was missing it is clean. A stretching-pin is in either case susceptible to impurity. A needle that has become rusty: If this hinders it from sewing it is clean, But if not it remains susceptible to impurity. A hook that was straightened out is clean. If it is bent back it resumes its susceptibility to impurity.