Why don't you remove the top case and check if there are stains spots on the logic board ? You could then clean the residues with isopropyl alcohol and Qtips. You can also connect an external keyboard and mouse to the unit and power it without the top case to test the machine. There are two power pads on the logic board that you can trip with a small flat screwdriver to power the machine. Check for the power icon or the words POWER BUT. Concerning the keyboard, I would replace it if the machine is still functional cause there's no way to clean it without take it apart and clean the internal layers and conductive traces.