Can you recycle an already exhausted rune to pay for a card's recycle cost (like Defy's 1 rune requirement)?

Ruling: Yes, you can recycle exhausted runes. The recycle cost can be paid regardless of whether the rune is readied or exhausted.

Nuances:

• All runes have both an exhaust ability (add 1 energy) and a recycle ability (add domain-specific resource)
• The recycle cost is independent of the rune's current state