Make the bamboo surface wet, and scrub with a stiff brush. This cleans deep into the bamboo and removes grime and fungi. A small amount of soap can, if necessary, be used.
When the bamboo is dry, use a power sander to sand the bamboo, just like a solid wood treatment. Start with a medium-coarse sandpaper, and when the desired removal is achieved, step up to a fine sandpaper to finish the surface. Make sure to sand the bamboo evenly everywhere. Be sure to sand with the grain.
After cleaning and sanding, it is important that the surface of the bamboo is sealed immediately with oil again. Apply according to the instructions on the product label, making sure not to apply more than necessary.
Let the oil dry and enjoy your bamboo product.