Washing TemperatureDrying TemperatureWashing Timesurface scratchPCB exposed to air too longBlocked nozzleSurface oxidationAbnormal thicknesscomponent oxidationSmall water containerConfuse the uncleaned board with the cleaned onesUneven thicknesscomponent oxidationDrying TimeUnstable DI water pressureTouch the PCB board by handDust in the airHigh density componentHigh humidityNot familiar with the machine/ processSmall compress air filter