Help removing shadows

I photograph historical maps and sometimes they're protected with a plastic laminate covering, which makes it very difficult to get a good photo - There are always shadows on the photograph. Photographing on an angle isn't an option, so I was wondering if anyone could help me remove the shadowing effect on these types of photos.

I wish I could show a photo, but this post won't allow me to insert a photo or a URL.


Thank-you.

you could fiddle with

image>adjustments>shadows/highlights, may help

mask out the shadows too