Whilst still on this thread, can I recommend a nice piece of software
called "Click Repair", developed by Brian Davies of the University of
Canberra in Oz.  It is the most intelligent, low-cost click and crackle
repair program I have used in a long time, either in manual or auto
mode, for 78s and vinyl LPs.  I'm on a Mac computer but it is also
available for Windows.  It's shareware but not expensive, about $30+,
I seem to remember.  Go to  http://wwwmaths.anu.edu.au/~briand/sound/

Best wishes, Tony Dellaway (France)