You cannot delete a client so this is the perfect way to do some house cleaning on the transactions your old clients had. To do this, simply click on "Full Report" in the Billing History of a client. Then, select the line items/transactions that you would like to archive. You can select all the transactions all at once by scrolling down to the bottom of the page and clicking on "All". Once you have selected the transactions that you would like to archive, click on the button "Archive Selected".