Flathead crusty rust under the intake manifold

Good evening,
I had an engine into the machine shop last year and they tumbled it and it looked pretty good. I put the engine on a stand to start relieving it but then got busy with other projects. This spring the shop flooded when the snow melted. The high humidity caused some surface rusting but I also noticed the lifter gallery under the intake manifold is very rusty.
I have been struggling to find a solution to my crusty rust issue so I thought I would search the forum but did not find any results that really answered my specific issue.
Is there a good method to remove the crusty rust from the lifter gallery?
I appreciate your input.

 

You need to ask this on the main forum not here in the intro section. More folks will see it there.