tool
Safety razor sharpener
There are different models of sharpeners for sharpening the blades of a
safety razor (1). In the past, people used a razor strop on which they
pushed the knife back and forth. You can also use a concave oil stone to
sharpen the blades. [MOT] (1) DURBIN G., Wig, hairdressing and shaving
bygones, Oxford, 1984: 21.