The method is a good one, but corrosion on the motherboard will be easier to remove doing this:
Honestly, liquid damage can be a hit miss situation. The cheapest but an efficient way would be to grab Isopropyl alcohol (preferably 99%), and a tooth brush. Apply a small amount to the tooth brush a go around the areas affected, then let it evaporate for 10 minutes. Repeat this step at least 3 times. Before assembling, let it dry for around 20 minutes, and make sure any corrosion is gone.