Talino,
we toss around terms these days to the point that I think we all get confused from time to time. I would say that in my opinion, a wash is aplying a very thin solution of paint to the figure in a less controlled manner. Where glazing is a very purposeful application of thinned paint to a certain area. For instance, a wash of black paint can be aplied to chain mail by thinning it way down (say 90-10 thinner to paint) and applied loosely to the mail so as to get it down in all the small nooks and cranies. In a glaze, all though you have thinned the paint you are applying it only to a designated area, say the tops of folds if you are doing final highlights. Glazing is a process of very slowly building up the paint in a certain area. The thinned paint allows more control and better blending. Usualy used with acrylics and enamels. HTH.
I would be careful of adding a wash of oils to your figure if it already has paint on it. Make sure it is very very dry before you attempt it. I would also make sure that you do not rub any area accesively or you will likely disturb the underlying paint already there. If you have used oils already, I would go in with very thin acrylic glazes and see if you can't bring up the desired results moving slowly and precisely. HTH,
Jay H.
OKC