Cal. Fin. Code § 1644

Any documents, letters, or other articles which, in the judgment of an officer of the bank, have no apparent intrinsic or marketable value, need not be offered for sale. The documents, letters, and articles and any other articles which have been offered for sale and for which no purchaser has been found, shall be retained by the bank for not less than one year from the date when notice of sale was mailed. At any time thereafter, unless sooner delivered to or on the order of the person in whose name the receipt was issued, the documents, letters and articles may be destroyed in the presence of an officer of the bank and of a notary public.