From the Holy Office under St. Pius X in 1910:
"For the future all the faithful already inscribed or who shall be inscribed in one or other of the real Scapulars approved by the Holy See (excepting those which are proper to the Third Orders) by what is known as regular enrollment may, instead of the cloth scapulars, one or several, wear on their persons, either round the neck or otherwise, provided it be in a becoming manner, a single medal of metal, through which, by the observance of laws laid down for each scapular, they shall be enabled to share in and gain all the spiritual favors (not excepting what is known as the Sabbatine Privilege of the Scapular of Our Lady of Mount Carmel), and all the privileges attached to each.
"The right side of this medal must show the image of Our Most Holy Redeemer, Jesus Christ, showing His Sacred Heart, and the obverse that of the Most Blessed Virgin Mary. It must be blessed with a separate blessing for each of the scapulars in which the person has been enrolled and for which the wearer wishes it to suffice. Finally, these separate blessings may be given by a single sign of the cross (<unico crucis signo>), whether in the act of enrollment or later at the convenience of those enrolled, it matters not how long after the enrollment or in what order they may have taken place; the blessing may be given by a priest other than the one who made the enrollment, as long as he possesses the faculty, ordinary, or delegated, of blessing the different scapulars-the limitations, clauses, and conditions attached to the faculty he uses still holding their force. All things to the contrary, even those calling for special mention, notwithstanding" (Holy Office, Rome, December 16, 1910).
While I had HEARD that there needed to be some reason not to wear the actual scapular (i.e. it's dangerous perhaps when working with machinery ... or if you're sweating a lot with heavy manual labor), this does not appear to be the case.
Now, my problem is that I was enrolled in the 5-Fold Scapular by a priest in the Chicago diocese, Father Cepon or Cipon (sp? -- perhaps someone has the correct spelling as it has been many years). Normally only Redemptorist priests have the faculties to bless the 5-fold scapulars but Father had obtained the faculties from the Redemptorists. Father was an interesting case. He had a small parish church in Chicago and continued to offer the Traditional Mass until he died (he was still alive in the early 1990s when I met him). He regularly welcomed us SSPX seminarians when we were in town. I heard from people that knew him that he had been close friends with Cardinal Cody and received permission to continue with the Tridentine rite in perpetuity. Evidently even Bernardin (who hated the idea) either felt he couldn't rescind it based on how it was written up. Or perhaps Father had some dirt on these Cardinals?
In any case, this says that the medal has to be blessed by priests who have the faculties to bless them, so I doubt I could find an undoubtedly-valid priest who has the faculties to bless the 5-fold scapular.