We discovered that rubbing bulk solids of C₆₀ between fingertips generates nanoparticles including the ones smaller than 20 nm. Considering the difficulties usually associated with nanoparticle production by pulverisation, formation of nanoparticles by such a mundane method is unprecedented and noteworthy. We also found that nanoparticles of C₆₀ could be generated from bulk solids incidentally without deliberate engineering of any sort. Our findings imply that there exist highly unusual human exposure routes to nanoparticles of C₆₀, and elucidating formation mechanisms of nanoparticles is crucial in assessing their environmental impacts.