[78-L] NBC Instantaneous Reference Recordings

[agp]

I have an NBC Instantaneous Reference Recordings -- are these 
acetates -- from 1956 of Andy William's Cadence recording Baby Doll 
-- 78 rpm of course - 10 inch. Now as to why they'd have made a dub 
of it, I dunno. Its a wee bit dirty and so I am wondering what is the 
best way and solutions to clean it. Any ideas on that, and conjecture 
as to why this dub may have been made? Hmm --  I also wonder if they 
(NBC) did these thingies in other speeds and sizes?

T