Looks like a nice recap job. For sound, you could also try playing through the 3.5mm jack, I seem to recall if you get no sound there, it might be an issue besides caps.

After installing new caps, washing the board is a bit excessive. I would just swab the areas that have excess flux with some alcohol. A little flux left behind is not nearly as harmful as acids from leaky caps unless you are using very aggressive flux, but I would only use rosin (some times in the solder core) or no-clean flux.