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You need to check back frequently to see if a page is always serving public service ads.
And when you do find pages that are always serving PSAs, try to figure out why. You might be able to make an easy change to get more targetted ads.
You could hack something together using the visualbasic/WSH sendkeys command - but this will rely on your site either having a naming convention that can be run through a for-next loop (folder1/page1.htm, folder1/page2.htm, foldern/pagen.htm) or being able to extract a list of filenames from your development tool and having your code process that.
There are also proper GUI testing products that would do a better job - but they tend to come at a hefty price.