These guys just ate so many members of Hive Fleet eWhore.
I use a product called "Kels Magic Sauce" which is an acrylic wash. Its $6 for a 2oz bottle and I don't have to worry about my ink ratios if I were to run out of a "homemade" say Chesnut/Water mix. It takes some getting use to as the surface tension is a bit lower than ink.
The wood stain is oil based so you're dealing with a completly different daemon. Messy, messy stuff. Its cheap and effective, but such a pain in the arse to use as it gets everywhere.