Even an experienced conservation and restoration artist finds working of such photographs to be an extremely challenging undertaking that requires good knowledge of materials and restoration techniques.
An attempt by an amateur who think that just about anything can be fixed with Super Glue or clear tape, can be utterly disastrous, resulting in further damage if not a total loss of a piece of great personal or historic value.
In most cases a damaged photo medallion can be restored by application of solutions specially formulated for make the material pliable again, and by using adhesives, which are known not to produce any dangerous chemical reactions, to fix the separated pieces in their proper places. In cases when damages are too severe or if large areas of photograph are lost, a photograph still can be restored by making a reproduction with all damages digitally retouched and lost pieces replicated.