With a mixture of soda and water. (toothbrush is what I use)
Try to get hold of some PCB cleaner in spraycan.
This is electrically non-conductive & will remove the
excess solder flux from the Bvision board as well.
But as Tesral said
"GET THAT ACID OFF THE BOARD ASAP"
It will eat the copper tracks & if the board is multi-layer
It may not be an easy fix
:-?
