Adding snow to terrain without eventual yellowing?

[Philhelm]

I'm visiting from the Frostgrave subforum.  I have read many different methods for adding snow to terrain and bases, but my primary concern is the yellowing effect some people have warned about.

What are the best methods to add snow to terrain that will not yellow over time?

[Dags]

Do not make a yellow snow joke, Dags

Do not make a yellow snow joke, Dags

Seriously, don't

The answer is twofold; don't cut corners using cheap materials and varnish before adding the 'snow'

[FramFramson]

varnish before adding the 'snow'

On the plus side, if you get frosting this is the one time it's perfectly fine!

[Philhelm]

What materials should be used?  I've seen some recipes that use PVA, white paint, and baking soda, but some have suggested that it will yellow over time (because of the PVA, allegedly).  I'm specifically looking for a snow recipe that will not discolor eventually.

[SteveBurt]

I used earth colour, heavy dry brush with off-white (Liquitex Parchment), then put blobs of PVA and dunked base in talcum powder (Johnswon' Baby Powder, but brand not important!)
The talc looks like snow, smells nice, and stays white.

[AndrewBeasley]

Do not use wood glue - ruined many a base with this 

I paint the base white with a grey dry brush, pva over the area then sprinkle Woodland Scenics Snow and white glitter on this.  The white glitter was a Christmas purchase (Sainsbury clearance sale) and just adds the sparkle I like.  Do not use silver glitter as that just looks wrong.