How Do You Keep a Safety Razor Blade Sharp?

Old School razor blade bank razor blade slot Blade Slot: 2mm x 55mm; Can fit 100 double edge safety razor blades razor shark slot demo The blades would slip through the slot and then cascade down into a gross little pile of disposed, used blades, and sit there for decades until

razor blade slot in medicine cabinet A couple pounds of razor blades in my wall Apparently old medicine cabinets have a disposal slot Overdone