Blueberry I bought masking fluid recently too as my last three classes used it. The one instructor used it a lot on our final painting. He mixed acrylic and water paints. To paint a river in the woods. Mine was so-so. Most of the students have taken his classes before and were familiar with his technique. My last class was the watercolor of birches. She used the masking fluid for the trees. That was more straightforward and easier. I want to practice doing the birches in the woods so I got some for me.