The idea of a blade or flat object to lighten it uniformly sounds very difficult. I would think that you would end up with patches or streaks of different shades. That would be harder to explain than the darkness to begin with. A couple years ago I masturbated for a few minutes a day with primrose oil and an exfoliating scrub. I got the idea from a thread about regaining sensitivity and smoothing the glans, as mine is rough. I noticed some improvements on the glans. I would recommend this over the pumice stone.