the glass working lathe sets the handling rods 105 107 and therefore the connected preform 101 into rotation in rotation direction 111 furthermore the glass working lathe has a controllable translation device not shown which comprises a plasma burner 121 and etching reagent nozzle 131 mounted on a translation stage 135 the translation stage 135 is moveable along a removal forward pass 141 and removal backward pass 143 the plasma burner 121 is an inductively coupled plasma burner the etching reagent nozzle 131 is constructed so that etching reagent flowing through the nozzle 131 is sprayed into the tip of the burner flame 123 of the plasma burner 121 by controlled movement of the translation stage 135 in removal forward and backward pass in translation direction 144 the removal positions along the preform 101 are set additionally the glass working lathe has a sensor unit 137 with a temperature sensor 138 and a diameter sensor 139 the sensor unit 137 is mounted on a translation stage which is independent of the translation stage 135 the removal process is used to remove the cladding 104 of the preform 101 therefore the translation stage 135 is moved to the connection point between handling rod 107 and first end of the preform 101 furthermore the plasma burner 121 is ignited so that the highest temperature of the burner flame 123 is applied to the surface of the preform afterwards the translation stage is moved in removal forward pass 141 if the burner flame 123 and the etching reagent nozzle 131 reach the preform 101 the etching reagent comprising 50 sif 4 and 50 nf 3 is applied to the tip of the burner flame 123 and therefore.