36°NaOH 1%~3%; Perchlorate 15%~20%; synthetic detergent 5%~8%; bath ratio 1:25~30; 98~100℃; 20~30min (until all color is removed). After all color is removed, gradually cool down, wash thoroughly with water, then use 0.5ml/L acetic acid at 30℃ for 10min to fully neutralize the alkali remaining on the nylon, and then wash with water.