The technique on it self is quite simple and gives a stunning result. much better then doing it by brush or sponge. It's just a bit more work. I might do a tutorial on it myself when I'm going to do the next bit of Manufactorum.
As you can see I added some "motivational" posters to the walls for added realism. Quite fun to do and I like how it turned out. I just made these little banners on my pc with photoshop but on this scale I think even MsPaint would work. I scaled them to size and printed them on normal paper. then cut them to the right size and soaked them in some gryphonne sepia wash and stuck them on the wall without any glue or anything. Then I torn a bit of the edges and folded some corners as if the poster had been hanging there for many many years.
In the end I think I have got a pretty decent manufactorum ruin but as I said this is only 50% of the work because I'm going to glue them on some MDF and make the floor and add some debris. I will keep you posted.