Here is a step-by-step guide to refreshing the varnish on a floor: 

1. Ensure surface is even: To achieve a beautiful refresh, it is important that the varnish is present on the entire surface and that there are no bare spots. 
2. Clean the old varnish: Use a soap for varnished surfaces to thoroughly clean the old varnish. 
3. Sand the surface: To ensure maximum adhesion, use a 220 grit sandpaper to sand the surface. The varnish must be sanded before applying a new product. 
4. Dust off: After sanding, dust off the surface well. 
5. Apply the first coat of varnish: Apply a first coat of varnish and wait for it to dry completely before continuing. 
6. Apply the second coat of varnish: Apply a second coat of varnish without sanding. Make sure to respect the drying time before using the floor again. 

By following these steps, you can refresh the varnish on your floor to give it a new appearance.