Three experiments were conducted to evaluate several combinations of pre-separators and cyclones for the collection of gin trash from stripper cotton. Pre-separator efficiency increased as the critical velocity inside the pre-separator decreased. A 90-percent-efficient pre-separator design reduced dust emissions from a 2D2D cyclone by about 9 percent, but offered no such improvements for a 1D3D cyclone. In 2 of 3 experiments the pre-separator actually tended to increase emissions from the 1D3D cyclone. This adverse effect was attributed to a problem of lint re-circulation in the cyclone's cone section near the trash outlet. Pre-separation tended to exacerbate this problem, especially for the 1D3D cyclone.