Create a mixture of 1/2 tablespoon mild liquid dish soap and 4 cups warm water. Stir the ingredients to create a sudsy mixture.
Dampen a plastic-bristled scrub brush with the soapy water and clean the affected section gently to remove any loose dust and dirt. Wipe down the bamboo with a soft cloth to remove the excess moisture and soapy residue.
Sand the frayed bamboo section with fine-grit sandpaper. Use even, back and forth motions to eliminate the frayed edges until the damaged section of bamboo reed is completely flat.
Repair the damaged section of bamboo with wood filler that closely matches the bamboo’s color. Apply the filler to the section with a gloved finger or spread it onto the bamboo with a razor blade. Remove any excess filler with a damp cloth.
Allow the filler to dry for at least eight hours, or overnight, before covering the bamboo with varnish, shellac or paint, depending on the existing finish.