Typically, the easiest way is to right click on the Recycle Bin on your desktop and select "Empty Recycle Bin". Sadly, you failed to tell what email program you are using so it is impossible to tell you how to permanently delete emails - but for most programs, you just go to the Delete folder and delete the emails from it. You normally are prompted, asking if you are sure you want to permanently delete those files. You also failed to tell us what version of Windows you are using, but if you right click on the drive in My Computer and select properties, you can use Disk Cleanup on the General tab to rid the drive of all clutter, temp files, cookies, and deleted files. Alternatively, CCleaner is a good cleaner of crud. BUT again, your emails will have to be deleted from the email program - disk cleaners do not delete old email, even if they have been deleted in the email program.
