John-
hot-tank it first, then fine wire brush/die grinder/brake cleaner works very well to get the case looking nice.
Another possibility: remove all the plugs, hot-tank, then plug the oil relief pistons, bead-blast the case (BEFORE you put in the squirters). Obviously do a very thorough job cleaning out any media, re hot-tank, etc.
I would NEVER bead-blast a case that already had squirters installed.
This is a bead-blasted '65, that then had the squirters installed :
Cheers
Scott