A preliminary review shows some city agencies may be abusing work credit cards. Mayor Rahm Emanuel sent out a letter last week to the Chicago Housing Authority, Chicago Public Schools, City Colleges of Chicago, Chicago Transit Authority and the Chicago Park District to order them to stop using work-issued credit cards. Employee reimbursements are also suspended while City Comptroller Amer Ahmad conducts an audit of related policies. An Emanuel spokesman said much of the potential misuses came from the CHA and park district, and includes things like paying off red-light camera tickets and expensive gifts and dinners.