How do I calculate the fair market value of my personal possessions, mostly books, vintage computer parts, furniture and such?

I own a considerable amount of vintage computer parts (Commodore 128, Amiga, 1980's & 1990's PC parts.)  I have a single modern computer that would only have been considered new in 2008 or 2009.  I have maybe 100 books, all old and many actually losing spine, or with pages falling out (extremely well read.)  Considerable amount of software, again mostly from the 80's & 90's.  A small amount of furniture (all old,) and a few kitchen appliances.  In doing my taxes and calculating insolvency I put in numbers I felt were fairly large over estimations of these values, but am not sure if that is exactly safe.  Is there any sort of guide to tell me how to calculate the FMV for all of these items, that most people would consider junk, but that a few might consider somewhat valuable?