First, make your book - for these samples I've been working small, about 5cm square. This is a sheet of tissue paper (that happened to be floating around) folded and torn rather than cut. I drew lines with a permanent felt pen, first along one diagonal and on the next page along the other diagonal. There's some bleeding through the thin paper. Then, out came the spray bottle -
Different black inks, different colour compositions -- rather like the effects you get when discharging black fabric. Using bleach on various inks will be interesting.
And finally - the bag that the Muji pen came in - simply sprayed with water and left to dry -