Removing outer layer of book covers

I have some books that need repair.  The covers are ... cardboard
that is very worn and acidified but the book contents are in good
shape.  I want to replace the boards with acid free stock then reapply the
photograph or other original cover.  The problem is that on
the front cardboard cover (and sometimes the back as well) the paper is
glued directly to it. I can't seem to find a way to remove the paper
without tearing it.  A couple of them are photographs which are not
repeated within the text so their loss is important.  Some photos are in
rather poor shape but are still informative.  I have no idea what kind of
glue was used.

I have on hand Bob's Wetter Water Book label remover which can be used
in some circumstances but have not tried this yet.  Any suggestions
would be appreciated. Thanks :)

Ms. Claudia M. Stall, Head
Collection Preservation/Mendery
619-594-2591

                                  ***
                   Conservation DistList Instance 8:7
                  Distributed: Thursday, July 14, 1994
                        Message Id: cdl-8-7-009
                                  ***