...And I thought I was the only one with this problem :-) :-)
Yes, it's the HelpViewer that has a nasty habit of leaving files lying around in /tmp. The files all begin with hvtmp:
...
796290 Sep 18 1991 hvtmpAAAa21088
796290 Sep 18 1991 hvtmpAAAa21319
796290 Sep 18 1991 hvtmpAAAa21954
...
And yes, they all seem to have that same date, Sep 18.
As a previous poster already stated, these files are left behind when OpenWindows is shut down without first quitting the HelpViewer. After a few days of "tmp filesystem full" messages on all of our student workstations, I finally just added a crontab entry to trash these things every couple days.
I wish there was a way to delete those hvtmp files as part of the OW shutdown process, but I guess it's really HelpViewer that needs the bug fix (ahem.."feature").