Cleaning up e-mail server after download

How do I get the program to erase the e-mail from my earthlink server after it has downloaded it to my Emclient program. This is a great piece of software and a great e-mail program, but I would like to have it erase my e-mails from the server when it downloads them.

are you using POP3 or IMAP for receiving your emails?

Thank you,