Cleaning Block for Head Install

We have had the head rebuilt on our slant 6 225 in a 1968 Valiant, used as an everyday driver. During rebuild time, the block has acquired minor corrosion in the cylinders and on the head face, and I'd like some guidance on the rust removal, along with any words of wisdom for the rebuild. If there are other posts that address the cleaning specifically, please pass links along. Thanks for a great site and your experience.
Dawn & Bob

Rumblefish has you on this.
I like oil with it so it keeps anything from spreading or falling down between the cylinder and piston.