* foam pedicure toe separators hold 4 bobbins ($ Store)
* pony tail holders ($ $tore - a gazillion for a buck or two!)
* there are "official" plastic clips that you can get at sewing stores
* cut to size piece of painter's tape (I use the tape more-so when I have a cantankerous spool of thread that has a mind of its own!
Mostly I use the pony tail holders or the plastic clips.
The toe separators work great when I wind several spools of a colour for one project.
Or when I am taking supplies with me for a sew-away.