Boston Red Sox 47 Clean-Up - Greyhound - St. Pats. As sleek as the dog it was named after the Red Sox Clean-Up Greyhound hat is made from 100% cotton twill. Our grey tonal relaxed cap has raised cotton embroidery of the Red Sox B logo on felt and features and airspray wash, creating a vintage weathered look with a shamrock on the back side of the hat. One size fits all. Cloth adjustable strap.