Best method to fix water damage with isopropanol? Is my method good?

John Taylor, yes that will work. You do not have to leave it to soak nor do you have to leave it to dry for 12 hours. The alcohol will dissipate quickly. The trick here is that you will have to repeat the brushing and cleaning a few times. Do not use any compressed air to dry the board since that could potentially drive moisture/debris under components and cause a short circuit. Check this guide for some really good ideas:-) just remember that you will always have to remove the EMI shields for a complete cleaning.