Try 
http://www.knightsolutions.com.au/files/apps/spinrite%205/
This program runs on any IBM compatible.  If you have such with the correct
drive type then this program will exhaustively test and repair the surface
of any drive you care to test.
----- Original Message -----
From: "chris" <cb(a)mythtech.net>
To: "Classic Computers" <cctalk(a)classiccmp.org>
Sent: Wednesday, February 04, 2004 7:39 AM
Subject: Re: Restoring old floppies to usable state
  I'll run a few disks thru a PC to use better
surface testing tools (any
 of my good Mac tools are either not readily available, or will only run
 on newer macs that have problems with 800k disks in the best of
 situations, so I wouldn't be able to trust the results to the disk or the
 mac being the source of error)
 Thanks
 -chris
 <http://www.mythtech.net>