All wages and accrued vacation or paid time off (PTO) earned but unpaid are due and payable:
The 72 hours is clock hours—not business hours. You are not required to pay accrued but unused sick leave upon termination unless your sick leave is incorporated into a PTO policy.
If you fail to meet these timelines, you will be responsible to pay an employee one day of pay for each day the final pay is late, up to a maximum of 30 days.
If your payroll company is out of state or unable to cut a check to meet these timelines, any form of payment is acceptable—you can run the payroll, determine how much is owed and pay the employee that amount by check, money order or cash. Payroll can handle the deductions later. If the employer pays in that manner, the employee must still receive an itemized statement. It can be handwritten or typed on a piece of paper if need be. Otherwise, the employer is subject to cash pay penalties in Labor Code Section 226.3. Ensure you get a signed receipt from the employee if you must follow this process.
For more information, read Final Pay Explained in the HR Library.