Related Clues:
- It's hard to get a thread inside it
- Sounds as if the colonel is off his head in there
- The sap is off his head - a hard case
- Hard outside, thread inside
- Partner of 44 Across
- Macadamia, e.g
- Cashew or almond
- Pistachio, for one
- Filbert, e.g
- Brazil is one
- Trail mix tidbit
- See 8
- Unconventional word that is taken out
- Head teachers
- Food which might be bolted