Make sure the surface is clean, dry and free of waxes and coatings, and let new grout cure at least 24 hours. Mask off adjacent areas, then apply a liberal, even coat with a low-pressure pump sprayer, roller or paint brush. Let the sealer penetrate, spreading any excess to ensure even coverage, and wipe off all remaining sealer before the surface dries. Apply a second coat on more porous surfaces 30 minutes after the first. Always test an inconspicuous area first (24-hour cure) to confirm the desired result. Do not aerosolize.