Thank you, thank you, thank you and thank you!!!!!!!! I love "ifixit".
I had a macbook with water damage. So I open the macbook and diassemble all parts. Then I follow these instruction and clean the logic board with toothbrush and isopropanol. I even clean bottomside of the cpu and gpu with isopropanol and pressed-air. Before that I diassemble the head sink and after that I appy new thermal paste.
So I put all together and it WORKS!!!