stacking
n.— «In an effort to save time and money, the company developed an illegal shortcut to force grease into the sewer system, according to U.S. Attorney Karin Immergut. The practice, known as “stacking” or “doinking,” can clog sewer lines. The company used the practice while removing grease from restaurants in Washington and Oregon.» —“Illegal grease disposal leads to $150,000 fee” by Ashbel S. Green Oregonian (Portland) Mar. 16, 2006. (source: Double-Tongued Dictionary)