the method comprises a combination of chemically treating the contaminant materials which adhere to the synthetic material for recycling with a mechanical recovery process , tumbling the product in a rotary drum . since only a small quantity of aggressive chemical solution is used in relation to the volume of products treated , the products are merely coated with the solution and never impregnated with it . in fact , even if a portion of the waste material is temporarily submerged , it immediately emerges due to the rotation of the drum . after this short submersion phase the treated products are dried by draining . for this reason the solution affects only the surface , that is , only the contaminant materials , and does not cause degradation of the valuable synthetic material , i . e ., the material which is to be recycled . the impacts caused by tumbling the waste material dislodge the adhering materials , already attacked and weakened by the chemical solution . these materials are dislodged from the surface of the treated waste and become insignificant in size as they are subjected to the multitude of impacts . a final rinse followed by one or more filtrations eliminates them totally . the aggressive chemical solution used depends upon the materials to be eliminated and may vary according to how resistant the synthetic material is to the treatment solution . as mentioned above , one synthetic material which is valuable for recycling is the polycarbonate used as a base for optical character reading disks . one side of these disks is printed and the other has an aluminum film protected by a layer of resin . conclusive experiments have been performed with two cubic meter quantities of waste optical disks introduced into a rotary drum with a six cubic meter capacity . the chemical solution consists of 20 % caustic soda at 38 ° c . and 80 % water . the volume of solution introduced into the drum is 20 liters , approximately 2 % of the total waste weight . drum rotation speed is regulated so that the waste material rotates around approximately 3 / 4 of the drum diameter for optimal tumbling . it is observed that the aluminum layer degrades very rapidly and the printing ink forms flakes which detach from the disk surface . the particles of detached materials become insignificant in size and the chemical solution progressively transforms into a homogeneous &# 34 ; juice &# 34 ; containing the contaminant particles . the operation takes about four and one - half hours . the next step is rinsing with water , also in a rotary drum , followed by filtration . if necessary several rinsing and filtration procedures are utilized . the solution used may of course be varied according to the type of waste treated . nevertheless , the treatment principles remain identical in every instance . chemical treatment is combined with mechanical treatment , and only a small amount of chemical solution is used so that the synthetic material is merely coated , and not submerged for a prolonged duration . examples of treatment of optical character reading disks consisted of the following steps : an alkaline solution consisting of 20 % soda at 36 ° c . and 80 % water was prepared ; a quantity of loose , uncrushed disks was prepared . this quantity was less than 50 % of the total volume of the rotary treatment drum used ; a quantity of solution , the weight of which was from 1 to 2 % of the weight of the waste to be treated was introduced into the treatment drum ; speed was regulated so that the waste material rose as high as possible within the drum without , however , effecting a complete rotation under the influence of centrifugal force . the mechanical and chemical treatment in the drum lasted from 2 to 5 hours until the layers of aluminum and printing ink detached completely from the respective disk surfaces and combined with the treatment solution to form a sludge . a large quantity of water within the rinse drum rinsed the disks until clean ; the rinse water was emptied and the disks dried inside the moving rotary drum by subjecting them to a stream of hot air ; the dried disks were moved through a crushing device to a storage silo ; the device for implementing the foregoing method consists of a rotary treatment drum 10 in which the chemical process as well as the mechanical recovery process take place , and a rotary rinsing drum 11 in which the recovered disks are rinsed and dried . a jet of hot air 12 is associated with drum 11 for this purpose . this device further comprises a crushing means 13 and a storage silo 14 associated with a device 15 for packing the crushed waste material . finally , the device comprises a vessel 16 disposed downstream of drum 11 for recovering the rinse liquid , a pump 17 for forcing the liquid toward a plate filter 18 which has at its outlet a reservoir 19 with an evacuation outlet 20 for the liquid , which may be reprocessed and recycled . the waste treatment procedure of the invention may also take place using only one rotary drum for both chemical treatment and rinsing . in this case the resulting &# 34 ; juice &# 34 ; would be evacuated through a turning connector .