Infernal Sources

Soul
Grind in Spite, requires Connected: Hell 10. If going for the Master Thief Accomplishment, you should also consider stealing them from the Brass Embassy

Amanita Sherry
Convert from soul. sells for 10 pence

Brilliant Soul
Convert from memory of distant shores or Amanita Sherry. You can steal it in the Flit from Thefts of a Particular Character, too. sells for 50 pence

Muscaria Brandy
Convert from memory of distant shores or Amanita Sherry. You can steal it in the Flit from Thefts of a Particular Character, too. sells for 50 pence

Brass Ring
Convert Muscaria Brandy, or gain them through The case of the fidgeting writer Held in weapons slot

Bright Brass Skull
Buy it from the Bazaar, or through The Relickers sells for 60 Echoes

Coruscating Soul
Gain this through The case of the fidgeting writer sells for 312 Echoes, 50 pence