High-quality single crystals of Bi,Se, were treated with hydrated hydrazine and the process was monitored by in situ conductivity and Hall effect measurements. The modified samples showed considerable shift of the plasma minimum. In the process of deintercalation, the location of plasma minimum changed back toward that of the pristine material. The similar monotonic and smooth variations of both plasma frequency and damping factor are discussed and conclusions about the dominating scattering mechanisms are drawn, based on considerations of an appropriate energy model.