Apply some paste flux to the bonding pad. Clean the bonding pad with Soldering Iron at 360℃. Then continue to apply medium-temp solder paste to the severely corroded pad. Clean with PCB Cleaner afterwards.

Continue to apply paste flux to the Flood illuminator module. Apply medium-temp solder paste to the severely corroded pad. Clean with PCB Cleaner afterwards. Once done, apply some paste flux to the bonding pad.