Type "df -k" and look at the result. Removing files in other filesystems won't help if / is full. You've got to remove stuff in the root filesystem. Note that /proc is a separate filesystem. That right there should tell you that looking at /proc is barking up the wrong tree. What's worse is trhat /proc consumes no disk space at all. It's a psuedo filesystem. Psuedo means make-believe. So ignore /proc and the other filesystems...if root is full, you've got to address that by looking at root.

If root has filled it's because someone wrote some files there. So a reasonable approach is to look at a recently written files in root...

find / -mount -mtime -10 -type f -print | xargs ls -l

The -mtime -10 says written to less than 10 days ago. You may need to adjust that.