oil washing

you probably could, but it depends upon the type of paint u used for the color scheme ( i.e. acrylic, enamel, oil......) the oils'll lift up enamel and oil paints, so it's best to apply an acrylic or Future coat over them to protect them. acrylic paints should have no problem.

the gringe

Gringe, I haven't had the problem with oil paint washes with enamels (non-coated). I have had this with acrylics though (definately use a clear coat). Was it the same effect as acrylics or a different effect?
Dmod