Meaning of blue bills

"Blue bills" typically refer to specific types of currency or financial instruments, often associated with U.S. paper money, especially the blue-colored $100 bill. In a broader context, the term can also denote proposed legislation in the U.S. Congress, where the paper used for bills introduced in the House of Representatives is often printed on blue paper. Additionally, in various financial settings, "blue bills" can refer to checks or invoices that are settled or paid.