I was going through some of my dad's stuff as he passed away last year. There are some razor blades that I found. These would have to be at least 15 years ago as that is about when he stopped using safety razors and started using a Excel Sensor or whatever was the rage at the time. The razors say Barbershop and Solingen - W Germany on them. Anyone know anything about these? Also, would these still be sharp after so many years or do they dull with age?