Popp
Popp is a simple and free POP3 email client. It features:
Multiple email accounts (passwords are encrypted when saved).
Allows easy and quick deletion of multiple emails — delete huge emails that are clogging your mail account, or remotely delete all your junk email, for example.
Quick preview a message sitting in a remote POP3 server.
Proxy Server Support.
If you’ve deleted multiple messages, you have the option of undoing your changes before you disconnect.
It’s free!