DIY Record ...sort of

[6GH8cowboy]

The year is 1949 and a young girl who would later marry and become my mother records a record sponsored by a local radio station. This 78 record is aluminum disk with what seems to be a lacqer coating. I played it on a USB turntable made for 33 1/3 or 45s. and adjusted the speed via the software to playback the file at the right speed. So far so good.
On a second attempt I noticed a light blue build-up of material at the stylus? Is the stylus too narrow? I cleaned the surface with a mild detergent and a cloth, is the coating disolving? I suspect this was cut on some kind of portable system that needed the "special" media blanks and perhaps were not intended to last a long time.
I would love to here any recolections of this kind of recording process, the machines used, marketing , etc. I suspect in 1949 this had to be a big deal to the general public.

Thanks
Dave C