There are several ways to do this:
a) If you have a linux or Mac at home, you can use the 'scp' command to copy files back and forth via the command line.
If you are a windows user, you can download a free SCP client called WinSCP by clicking this link here.
Note: If you are not a CS student but have an ECI account, you can use linux.engr.ucsb.edu instead of csil.cs.ucsb.edu.
Run WinSCP and fill out the information below, replacing jsmith with your ECI username and the password field with your ECI password (in section #1). Once you are ready to connect click Login (#2).
You can now drag and drop files between CSIL / ECI and you local computer. You can tell which one is which by looking at the bar above the directory and file listing (in this particular screenshot you cannot see the directory path).
Make sure to close the window and disconnect when you are done.
Note: You may also see files that are normally hidden when you view your directories on a CSIL machine, it is best to leave these alone.
b) You can use a usb flash key to copy files and store them. Plug the device in to a lab machines and copy your files over.