Don't pour used cooking oil or grease down the drain. Recycle if for free instead during the Holiday Grease Roundup. Beginning Nov. 22 through Jan. 10, Mansfield residents can drop off used cooking oil at the collection station at the Environmental Collection Center. The collection station is available 24 hours a day, seven days a week during this annual collection event. Collected grease can be recycled into biodiesal or biogas, and reduces landfill waste.