Wear nitrile gloves, eye protection, and a Tyvek or disposable coverall to keep resin and glass fibers off your skin and clothes. Use an organic-vapor respirator when working with polyester resin, gelcoat, MEKP, or solvents, and always keep the area ventilated. A simple dust mask is enough only for sanding cured glass, not for liquid resin or solvent fumes.