A very good control to have is that any non-purchase order approved payment requests should have audit support for the approval via an approved check request form, email, or the like.
For instance, someone needs to buy printer toner in bulk that costs $1000. The employee may verbally ask the AP department to cut a check to pay for the toner which seems harmless but in a Sarbanes-Oxley compliance world, you cannot prove that the conversation took place so you would need to put in procedures to make the approval process, auditable.
A great way to accomplish this is use a check request form. We have a great check request form that we'd be happy to give to you. Register at the top of the page on the right side or click the button below to be taken back to our home page where you may also easily register: