I've recently come across a problem: one of my Cpanel account had almost 300 anti-spam filters defined under "Account Level Filtering". It took me well over a year to build it. There is no straightforward way to export or copy these to another account so that you don't have to define them all over again.
The simple solution is to copy this file from the original account, with all the filters, to the new account:
Don't make any changes to it in a text editor, just copy it to the new account and access the list to view or modify the entries by going into the "Account Level Filtering" menu in CPanel.