1. Clean the grout: Before refreshing your grout, it's important to clean it first. Use a grout cleaner and a scrub brush to remove dirt, grime, and stains from the grout lines. Rinse thoroughly with water and let it dry overnight.

2. Choose a grout paint: You can use a grout paint or colorant available at your local hardware or home improvement store. Choose a color that matches your existing grout or opt for a different color for a new look.

3. Apply the grout paint: Apply the grout paint with a small brush, making sure to cover all the grout lines. Be careful not to smudge the paint on the tiles. If you do, use a damp cloth to remove any excess paint.

4. Let the paint dry: Allow the grout paint to dry according to the instructions on the label. Most grout paints take about 24 hours to dry completely. Keep the area well-ventilated to speed up the process.

5. Apply a sealant: To protect the newly painted grout, apply a sealant over the grout lines. A grout sealer will help to prevent stains and keep your grout looking clean and new. Follow the instructions on the package for best results.

By following these steps, you can refresh your grout and give your tiles a fresh look.