Well not only did I spill gesso on the rug I also left one of my favorite brushes in acrylic paint for several days and you know what that does..it petrifies the brush as we all know and have probably done. Well don't throw it away so fast. Bob Burridges has great tips and this is one that works! He washes all of his brushes with Murphy's Oil Soap and makes them all like new. If you petrify a brush just soak it in Murphys for 24 to 48 hours and it dissolves all the paint and makes it like new. This brush is like new again. Good ole Murpheys! It's magic stuff!