I have the Q&D bass traps in my room. The fglass is wrapped in plastic to avoid any fibres getting out, (hopefully). I then covered them in burlap. Not the prettiest, but they sure do knock down the boomyness. Since I'm fortunate enough to have pretty well taken over the rec room for my listening room, the WAF isn't extreme and I can get away with plain old burlap. Grille cloth would look a lot nicer, but would also cost a lot more.