I suppose it's OK if one doesn't have any hair on their arm. The guy's arm looks like it's been shaved.
I wonder how an old leather belt would work. Hmmmm, maybe I'll try that. Tie it to the door knob and hold it taut.
On the other hand those blades cost less than $3.00 each. I purchased 20 at Costco for $55.00. Lasting 3 weeks that's a dollar a week.
Like that slogan used in women's commercials, "I'm worth it!"
He says that you have to swipe razor backwards up the arm, if you swipe it forwards it will only dull the blade further.
They sell a razor-sharpening machine, for anyone interested...
In the video it looks like his arm is shaved unless he has very little arm hair or I have a lot.
Are you sure that you are using your arm?