Q. If you find a common ordinary ballpoint pen that is similar to many others on a table in a shul or other frequented Jewish institutions, can you use it or even keep it?

A. Horav Shlomo Miller’s Shlit’a opinion is that if the pen has been abandoned for days or some reasonable time to assert that it was abandoned, and not just left there until the owner comes back, it could be used and kept.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a