Can I safely delete all the "0" size files in /home/username/tmp ?

[Josef Lowder]

In my /home/username/tmp/orbit -username directory, I have hundreds of files
of "0" (zero) file size dating back three years.  Is there any reason
why all these
files cannot be deleted?  And why aren't they automatically deleted at reboot
if the are, in fact, just 'tmp' files?

srwxrwxr-x  1 joe joe   0 Dec  9 06:33 linc-985-0-5ade3bcfbbb33
srwxrwxr-x  1 joe joe   0 Dec 15 07:05 linc-7a43-0-f80783d1f283
srwxrwxr-x  1 joe joe   0 Dec 15 07:15 linc-7aae-0-5a1a5effe7972
srwxrwxr-x  1 joe joe   0 Dec 15 07:15 linc-7ab0-0-7db99ee517913
srwxrwxr-x  1 joe joe   0 Dec 27 10:25 linc-4650-0-3a4016ed619f1
srwxrwxr-x  1 joe joe   0 Dec 27 10:25 linc-466e-0-2bd9b9541657b
-rw-rw-r--  1 joe joe 661 Jan  3 01:19 bonobo-activation-server-ior
srwxr-xr-x  1 joe joe   0 Jan  4 13:30 linc-6c0d-0-5efb73cbc5321
srwxrwxr-x  1 joe joe   0 Jan  4 13:30 linc-6bfe-0-744fa82528c43