The idea is this... future floor polish is an acrylic gloss finish. This will protect the paints underneath from the oils and allow me to rub off some of the black after its partially dry. The gloss finish allows the paints to flow nicely, and since its from a bottle I can airbrush it on. The oil wash is just a mix of thinner and artist oil paints. I'll be using black, but you could use whatever makes sense for the colours your are shading.
Tactical squad with the acrylic gloss coat
Closer look at the gloss finish
All ready for the oil wash
Oil wash applied
Ok to dry for a few hours