Dremel Tool bits tend to come in blow-molded containers.  As bits accumulate from different sources, the collection outgrows those containers or they don't fit well.  Here's a quick tip to organize your grindstones, cutoff wheels, saws and other assorted bits.

Strips of corrugated plastic, often used for yard signs, can be purchased at home center stores.  The ~ 0.157" material, available from several manufacturers, is perfect for storing 1/8" shank bits.  If cut into strips and placed in a suitable container with a secure cover, you have a perfect storage solution.

I think this container held an Ikea hardware kit prior to being purchased at a thrift store.

This will work will for 1/8" shank CNC bits as well.