Bamboo countertops are a natural alternative to synthetic material for kitchens. Bamboo is renewable, strong, and durable. Like any other woods, though, it's porous and prone to scratches and burns. To prepare the surface for kitchen use, you must seal it. This will produce a countertop that lasts longer and performs better than unfinished bamboo.
Sand the surface of the counter, starting with the 220-grit sandpaper, then moving to the 400-grit sandpaper. Inspect the wood carefully for any scratches and smooth the surface. Take your time with this—this process determines the look of your finish.
Apply two coats of tung oil as a seal. With each coat, spread the oil with a rag or paper towel and then go over the surface again with a dry paper towel, buffing away any leftover oil. Allow the countertop to dry completely.
Finish the surface with a coating of polyurethane or varnish, though you may leave it with only the tung oil. Test the combination of tung oil and finish on a scrap piece of bamboo before applying the finish to make sure the two don't repel one another. If the oil is completely dry, however, this shouldn't be a problem.