I want to share something I have discovered to be really helpful for applying masking fluid to my watercolor paper to retain whites.  These shapers are perfect for those especially small details you re trying to save white.  Like the white fleck of reflection in the pupil of an eye.  Tiny wisps of hair to be saved white or painted later in a light color.  Or I often use it for small fence posts, muttons on windows or spattering the masking fluid.  Another tip to note is that it is important to use masking fluid that has not begun to get thick.  Here is a link to Jerry’s Artarama art supplies as a place to purchase these shapers