Computer Sciences Corp. is selling off as much as $450 million in government IOUs to banks, in the company's latest strategy to improve financial performance. Falls Church-based CSC entered into an agreement April 21 with The Royal Bank of Scotland PLC, Mitsubishi UFJ Financial Group Ltd. and Bank of Nova Scotia to sell eligible receivables from its North American public sector group, including those already billed under an invoice and others from reimbursement contracts.