I do not know about the scruff holding, I believe it doesn't not hurt them.
However, I clip my ferrrets' nails by placing them on my lap, between my
legs, flip them belly up, drop some linatone on their stomachs and clip
their nails that way.  It enables me to use both hands on clipping, and the
ferrets don't wiggle or mind.  And I clip their nails once a week (keeps
them from scratching my legs to shreds when they try to climb up them when
they want to be picked up).
 
[MC]
 
 
>Can anyone suggest how often I should clip Rockies claws.  I also would
>like to know if holding him by the neck is painful or damaging to him ...
[Posted in FML issue 1536]