I started out using a large pill bottle, but then got a couple of those metal blade banks free with an order and now use those. What I like about the metal blade banks is that they are metal and clearly labelled as containers of razor blades. (And utility knife blades.). They hold two or three years worth of blades. And when full, I can just bang the slot closed, then pitch the whole thing in my metal recycling.
True story: I worked with a guy once who said he had once sold "solar-powered clothes driers" through newspaper ads. The product he sent the people was a clothes-line.
The house I live in now has a slot in the medicine cabinet. My old biscotti can started leaving rust stains on the counter so it was recycled after 7 years of use.
I just use an inexpensive blade. When I feel it is full enough, I empty the blades into an empty veggie can, or similar, stuff some paper inside to keep them there, and toss them in the trash.
Feather Blade Disposal Case. $10 on Amazon. https://www.amazon.com/dp/B004LDEISW/?tag=thshde-20 There’s another brand on Amazon for $3 less if the extra moolah is important to you…
My grandmother had a variation of this. Just a sealed can, no way to open it. It didn't have the buzz words that this one has, as it was made 50 years ago.