I have been using Polyfila for pretty much everything recently: it's naturally white for snow on Frostgrave figures.
It will mix with paint to make other colours, or you can just base paint it.
It makes good looking earth painted brown, or sandy desert for pirates painted light brown/yellow.
.....and a ready mixed tub goes forever and is much cheaper than GW speciality paints.
.... and the dried tea bag leaves stick nicely too.
Anyone have advice for straightening bent spears? Warm them up in hot water?
I have been making some TSS resin buildings which are pretty poor actually - panels are ropey castings, and they were quite bent and bowed.
It took boiling water in an ice cream tub, and then a weight on top to get them reasonably straight, and then there has been a lot of polyfilla filling gaps and holes.
I have used smaller containers and hot water to straighten stuff on figures, but you have to be gentle, and I find it best to prepare a way of lying the spear flat, and using some form of weight to press it straight - which can be tricky on some models.
I end up with convoluted support systems of blister sponges and lolly (popsickle) sticks.