Maybe some of you haven't tried to archive your mailbox messages and still left them there inside your Mail inbox. I cannot say that it's not good, but I can say that archiving your mailbox can save you mail space because it'll help you remove the attachment by saving only the plain text and also can help you organize better your incoming mail.

Archiving Mailboxes

This feature comes along with Mac OS X Mail. It's relatively easy to archive your mailboxes. What you need to do is highlighting mailboxes that you want to archive, click and choose Archive Mailbox.. or also can do Archive Feed...

Importing Mailboxes

It's also a piece of cake when you want to import your existing mailboxes; You only need to follow several simple steps :

1. Open Mail
2. Go to File ▸ Import Mailboxes
   
3. Choose Radio Button: mbox files
   
4. Select .mbox Files and Do the Importing