When it is found that the solvent recovered by the solvent recovery machine is yellow, green and colored, but it is still clear and transparent. Please consult the supplier about the material of the condenser of the recovery machine. Many times are due to the chemical reaction between the solvent and the condenser. For example, when recovering more acidic or alkaline solvents, the solvent reacts with the copper condenser, which will cause the recovered solvent to be colored. The solution is to replace the copper condenser with a stainless steel condenser.