Well as topic being reducing string noice in general when recording;
Tie a scarf right above the nut, prevents the strings rattle. ( I think "rattle" is the right word... :/ )
As presented here:
http://www.youtube.com/watch?v=QcanWkRbnwQSometimes when i record solo's / something from upper registers, i tie a scarf ON the strings right on first fret using very very light tension.
Again prevents string rattling & extra noises AKA. mutes the lower end of the neck.
Music stores also sell spray-type oils designed to reduce the action noice. Never tried 'em tho.