Georgia law on this issue may be different than other states. Look on Avvo.Com under Find-A-Lawyer and enter 'Business Law' as the area of practice (or in the alternative 'Real Estate Law'). Good Luck on this .
There are some issues in providing a concrete answer to this questions in terms of a "statute of limitations" on how long you have to hold onto someone's property before it is considered abandoned. Georgia law doesn't provide a timeframe and the courts seem to treat circumstances on a case by case basis.
Georgia code (OCGA § 51-10-1) provides that “[t]he owner of personalty is entitled to its possession. Any deprivation of such possession is a tort for which an action lies.” This basically means that if you are in possession of someone's property, you can't get rid of it or sell it or you are liable to be sued for conversion. To establish a claim for conversion, the property owner must show (1) title to the property or the right of possession, (2) actual possession in the other party (meaning you are in possession of his property), (3) demand for return of the property, and (4) refusal by the other party to return the property.”
Nowhere in these elements, however, is a timeframe. I have seen between 30 and 90 days being a sufficient amount of time to elapse before the property is considered abandoned. If a client came to me with this issue, I would tell them to make every effort to contact the other person in good faith, documenting your attempts. If he hasn’t replied within 90 days, the property is abandoned and you can dispose of it as you see fit.