brake noises are 95% of the time related to the friction material. Is slides look ok, I would just replace the pads, or as an alternative take some fine grit sand paper and sand the pads, after that used a mild dish soap and water and wash the pads, dont srub them, you are just trying to get sanded particles off them. For the rotors, do the same with sand paper or a whizz wheel and use soapy water to wash them.
Jon