Possible Clues:

• Can they be so secret with a prominent painter around?
• Taken up by con man, a crafty few cards
• Secret information
• Secret things revealed in ear can astonish
• Able to be secrets in a famous painter
• Discharge, in equal quantities, mysteries and secrets
• Insider info
• A right place for the miraculous mysteries
• Things known to only a few
• Esoteric stuff