"machinery or 37 equipment, such as belts, drill bits, grinding wheels, cutting bars 38 and saws, and other replacement parts for production equipment, 39 including refractory brick and other refractory items for kiln 40 equipment used in production operations; 41 [(ll) all sales of educational materials purchased for distribu- 42 tion to the public at no charge by a nonprofit corporation organ- 43" . . . .