“Always protect your own ass.”   If you, and no one else but you, wrote the material ... and you were not working for anyone else at the time ... then All Is Well.   But if not, Exercise Due Diligence.™   Find anyone-and-everyone who might possibly object, tell them everything, ask permission,™ and document in writing that you did so.   It’s just called, “common sense.”   If someone happens to notice and subsequently decides to raise a stink, you’re all set to assert the Innocent Infringement defense.   (And pray.)