Do you have any friends? Also, there are plenty of machine shops, auto repair shops, metal shops, plumbers, solar installers, fabricators, welders, and even bike shops on this planet where they own a buffing wheel and some one would do this for you for a tiny, little bit of money especially as was suggested to you already you certainly do not need to buff the whole handlebar just the part that shows. (minimal)

Please think of this as a very small buffing job. Do not see this as YOU have to have all the equipment and do the work yourself which I am guessing you would not do... in order to accomplish this tiny little job.