How can I refinish a table top using polyurethane?

To refinish a table top using polyurethane, follow these steps:

1. Sand the table top to remove old finish and smooth the surface.
2. Clean the surface to remove dust and debris.
3. Apply a coat of polyurethane using a brush or roller, following the wood grain.
4. Let the polyurethane dry according to the manufacturer's instructions.
5. Lightly sand the surface with fine-grit sandpaper.
6. Apply additional coats of polyurethane, sanding between each coat for a smooth finish.
7. Allow the final coat to dry completely before using the table.