Does anyone know what to put over the glitter snow on Santa's Workshop. Everything else is perfect.

Maybe new white glitter that is already mixed with glue?

I have that ornament too and want to "whiten" the snow.

I was told to sand lightly and paint with Testors paint and then sprinkle with glitter.

I just checked online and Hobby lobby has it for $1.99. White enamel flat and gloss.

I have a few ornaments that have yellowed. Hopefully I can restore some of them.

At first thought this was Frank Zappa reference

While I have never tried any of these methods; below is list of ways to whiten yellowed plastic. I'm not sure if this would work with glitter.
Of course anything with fabric or paper I wouldn't try with the submerged liquid methods.

https://www.tidylife.net/how-to-clean-and-whiten-yellowed-plastic/

A number of years ago I looked online about how to whiten plastic toy figures such as Star Wars, GI Joe, etc. NOT ornaments which are a different kind of plastic. Plastic containers are also made of a different kind of plastic than the ornaments.
It might be wise to buy a cheap ornament that needs to be whitened and experiment on that before attempting to whiten a cherished ornament.
Perhaps someone would ask HMK or one of the artists about whitening the ornaments.