Just make sure you comply with State law prior to imposing any fees:
(4) A holder may not impose with respect to property described in subsection (1) of this section any charge due to dormancy or inactivity or cease payment of interest unless:
(a) There is an enforceable written contract between the holder and the owner of the property pursuant to which the holder may impose a charge or cease payment of interest;
(b) For property in excess of ten dollars, the holder, no more than three months before the initial imposition of those charges or cessation of interest, has given written notice to the owner of the amount of those charges at the last known address of the owner stating that those charges will be imposed or that interest will cease, but the notice provided in this section need not be given with respect to charges imposed or interest ceased before June 30, 1983; and
(c) The holder regularly imposes such charges or ceases payment of interest and does not regularly reverse or otherwise cancel them or retroactively credit interest with respect to the property.
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