The demon Clauneck appears in the grimoires The Secrets of Solomon, Grimorium Verum, and Dictionnaire Infernal
From Grimorium Verum, Plangiere edition:
CLAUNECK has power over riches, can cause treasures to be found. He can give great riches to he who makes a pact with him, for he is much loved by Lucifer. It is he who causes money to be brought.