From a reader:
The prayers in the old Roman Ritual are sometimes much richer than the prayers found in the current Book of Blessings. Since the added exorcisms and petitions in the older prayers might make a sacramental more effective, is it ever permitted to have something blessed a second time according to the older ritual? If so, would this have to be a conditional blessing?
Well… I guess so. I think you would have to examine the prayers for the things in question and then make a determination.
The newer Book of Blessings (De benedictionibus) is filled with texts that don’t seem actually to bless things, in the sense of a constitutive blessing. The Book of Blessings has in the introductory section some theological comments which seem to eliminate any notion of the constitutive blessing.
While there are certain sacraments we cannot repeat, such as baptism, confirmation and holy orders (because they impart an indelible character which remains… even in hell or heaven), we are talking about sacramentals, not sacraments.
The bottom line is that, were you to have a thing blessed with the older Rituale Romanum that was already “blessed” (or not), no harm would be done. At worst you would have started with something already blessed which was blessed again. At best, you have something that wasn’t blessed that it now blessed. I don’t think a “conditional” form has to be used, as in the case of a doubtfully conferred sacrament.
Be careful, however, with re-blessings. My experience is that when you bless things over and over, they start to glow in the dark and float. Do this only indoors. You don’t want them to get away from you.