Corrosion on circuit board

[Neal]

I've got a digital piano in the shop that has been damp, and shows some corrosion and 'whiskers' on a couple of circuit boards. I figured I'd clean the board with a brush and re-flow all the solder connections. Does anyone have a recommendation for a solvent, i.e. degreaser or alcohol, or any tips or warnings before I start?

Thanks!
Neal