A tax break provided as an inducement to sell valuable items (especially art) to public collections rather than on the open market.
Sweetness of manner: agreeableness, gentleness.
A sweetener: a gift offered to sweeten another's attitude, a tip or bribe.
Money stored for illegal or dishonest purposes.
Money that has not been hypothecated or dedicated to a particular purpose, or which is used for a different purpose than originally intended.