Cost effective control of particulate emissions has become a major objective of most U.S. cotton ginners. An effective trash handling and emission control system has also become an essential element in modern high-production ginning. As a result, a lot of research has been conducted during the past few years to improve operational effectiveness of modern trash and particulate collection systems at U.S. cotton gins, and to further reduce particulate emissions to the atmosphere. A summary of numerous studies conducted during the past 5 years at Texas A&M and at the USDA ARS ginning laboratories on pre-separators for cyclones, various modifications and improvements to the conventional cyclone collector, several new cyclone designs, and the physical and chemical properties of cyclone emissions are reviewed in this paper.