Possible Clues:

• Room with muck, one that's awful?
• Underground place of confinement
• A long time after dropping cage
• Here one may finish a sentence underground
• Having done wrong with gun, cast into prison
• Place of confinement debt collector has no say about
• Having done wrong to hold gun, reformed in prison
• Where Dantes was held, in 'The Count of Monte Cristo'
• Dropping long stretch of time in underground cell
• Underground cell, none dug out