Possible Clues:

• Rusting
• Process that creates rust
• Going rusty, say, lacking energy needed to produce neat imagery
• Beastly type is an idiot boss - anyone working in the hairdressing industry will recognise this is a problem
• Electron loss, to chemists
• Rusting, lidless box hid a can containing nothing
• Rust formation
• Rusting process
• Bovine, silly idiot, an instance of becoming dull?
• Eg, rusting