A method for the continuous optoelectronic processing of a stream of particles of used synthetic organic materials to be recycled, which is in a fragmented form of particles made nearly homogeneous in composition, but remaining heterogeneous in coloration due to the presence of particles colored in their mass especially by cadmium compounds, characterized in that, to eliminate the colored particles from the stream of particle of synthetic organic materials to be recycled, with the method comprising the steps wherein: (a) a continuous stream of loose particles of used synthetic organic materials to be recycled, homogeneous in composition, is transformed, in a suitable area and using suitable means, into a stream arranged in the form of a single-layer curtain of particles separated from one another, free-falling at a given rate, (b) the stream in the form of a single-layer curtain of free-falling particles goes through an area provided with observation and recording optoelectronic means positioned opposite each other, on either side of the stream in the form of a single-layer curtain of particles, which record full images of each particle in the curtain (c) the optoelectronic means transmits, in real time, the full images of each particle of the stream in the form of a curtain, to software and image processing algorithms which detect, on line, the presence of colored particles of synthetic organic materials and determine the time and spatial coordinates of each colored particle to be eliminated from the curtain of particles, (d) the software and the algorithms transmit, in real time, the coordinates of each colored particle to be eliminated from the curtain of particles, to a eliminating means which eliminates each colored particle and releases a stream of particles of used synthetic organic materials to be recycled, homogeneous in composition and in coloration. (a) a continuous stream of loose particles of used synthetic organic materials to be recycled, homogeneous in composition, is transformed, in a suitable area and using suitable means, into a stream arranged in the form of a single-layer curtain of particles separated from one another, free-falling at a given rate, (b) the stream in the form of a single-layer curtain of free-falling particles goes through an area provided with observation and recording optoelectronic means positioned opposite each other, on either side of the stream in the form of a single-layer curtain of particles, which record full images of each particle in the curtain (c) the optoelectronic means transmits, in real time, the full images of each particle of the stream in the form of a curtain, to software and image processing algorithms which detect, on line, the presence of colored particles of synthetic organic materials and determine the time and spatial coordinates of each colored particle to be eliminated from the curtain of particles, (d) the software and the algorithms transmit, in real time, the coordinates of each colored particle to be eliminated from the curtain of particles, to a eliminating means which eliminates each colored particle and releases a stream of particles of used synthetic organic materials to be recycled, homogeneous in composition and in coloration.