Princeton catalyst brush #4 mini

Catalyst by Princeton

Tools that move paint Not quite a brush. Not quite a palette knife. Catalyst tools are crafted from flexible silicone to allow artists a new form of expression. Catalyst Blades are mounted on artist brush handles offering a blend of tradition and innovation.

Clean-up is a breeze with Catalyst Blades, the silicone is easy to wipe clean and is solvent resistant.
Clean up in most cases can be done with mild soap and water,  dried paint can be peeled off the silicone surface.