Even if you're currently DA/DF you can still collect any monies owed you by the Kingdom Hall as far as loans go.
We were able to get back $1000 that my mom had loaned the local hall for a loan to build new one.
It was documented by the paper that had been given each publisher back then on how much they could/would be willing to give as an outright donation or a loan. The loan was to be paid back whenever the publisher requested it. (not a specific date)
I can't help but feel that a lot of the old timers that loaned monies to the society and/or K-Halls have been forgot about by them or their families.