This method works well for brushes ‘stiff’ with masking fluid.
Soak the brush in a small amount of Zest-it for about fifteen minutes, it should feel soft and ‘gooey’ to the touch.
Gently roll the filaments between your fingers to loosen the masking fluid, remove the ‘gooey’ masking fluid with kitchen towel, then wash the brush in Zest-it. Repeat as necessary.
When all masking fluid has been removed, wash the brush and your hands in soap and water until clean.
Zest-it Masking Fluid Remover is not an aggressive remover, so patience is rewarded.