How to securely remove files:

Choose Trash > Secure Delete Files.

Choose the files you want to delete and click Select.
When you delete a file the physical data is not immediately removed from the disk. This has the advantage that the data may be recovered (albeit with difficulty) but poses a security problem if you want to permanently get rid of the data.
With MainMenu you can securely remove files to make sure their contents is immediately removed from the disk.
Choose Trash > Secure Delete Files.
Choose the files you want to delete and click Select.
MainMenu uses 7 US DoD compliant passes to overwrite the file with zeros, ones and random data to securely remove files.