I hope this is not yet covered by someone else, but it just occurred to me that a lot of magazine scans need cleaning because the image in the previous page shows through due to the poor paper quality. In which case, perhaps I can do this:
Level the page I'm working on
Level, Flip Horizontal, Inverse(color) the page behind it
Put the inversed backpage on top of the page I'm working on, as a screen layer at really low opacity
Also, because I'm using the same scan source, the Levelling is already saved as an action so that a) I get consistent result across all pages, and b) it's much easier/faster.