I am more of a lurker than poster however I just found this website www.BobbinKnobbins.com . They have this little foam shaped horseshoe that goes around your bobbins.
Since I'm a notion/gadget kinda of gal I had to buy some. They work great.
I have over 20 machine new and vintage and I use them. The Bobbin Knobbins fits on the bobbins. They come with a case that you can label for each machine ,so you don't have to worry about tossing them in a box and wondering which machine they belong to.