If you're not worried about any kind of corrosion, then it doesn't matter what sort of water is used. The point of using distilled water is that it doesn't have any ions in solution, and it's the ions that conduct electricity. However it makes no difference, because as soon as the DI water hits the stuff you're cleaning off, now you've got ions in solution anyway. If you care about that, then what you do is clean it first, then rinse with distilled water.
But yes, some type of alcohol would be technically best. You should also take it out of the case and wash the case as well, because undoubtedly some will be underneath. I don't think it would actually soak into the PCB itself though, it should just be on the surface. If you're unlucky some may have gone into switches which may pose issues.