Product description

ADDCORE Rust Eraser Save Your Favorite Cast-Iron Skillet

With this clever eraser, you can easily restore any cast-iron surface—including grill pans, griddles, grill grates, and tools—back to its original, tarnish-free state. Your favorite pan will be good as new in no time! Before you get to work, make sure your cookware is cool and dry. Then, start "erasing" and prepare to be blown away. Just like a rubber school eraser does to stray pencil marks.
The handy product revives your cookware by stripping it down to the bare iron. Because you're essentially giving your pan a new chance, don't forget to re-season it before putting it to use again in the kitchen. This also means all those flea market finds and heirloom pieces that may come your way have a second lease on life! So don't let rust deter you ever again.
If you too have committed this kitchen sin and need to know how to get rust off your cast-iron skillet, this eraser will save you.

What is this eraser made of ?

Silicone carbide and rubber, It wears down as you use it. It is easy to use. You use it like an eraser on the cast iron. Like most erasers, the eraser will leave behind pieces of itself as it cleans the cast iron. It did a great job on my cast iron.

Could this be used to clean rust off smooth surfaces like a knife? Would it leave large scratches?

I don't see why not. I have just used it for the first time on a small rust spots on my ridged griddle. Worked very well. You can use the rust eraser on anything made of cast iron or carbon steel. Can even be used on knives, tools, and grill grates!

Does this do they same job as chain mail, or are they different?

Chain mail is for cleaning stuck-on food. a rust eraser cleans off rust. rust is not the same as stuck-on food.

Will the rust eraser damage knife blade coating？I don't want to scratch the finish or rub off logos/writing

I don't see the rust eraser damaging the coating or the etching on the blade. you can take off just the rust. It's easy to use and doesn't take a lot of pressure.

Is it worth it or should I just buy steel wool?

This eraser is better. Steel wool removes metal and changes the surface.this removes rust, but doesn’t scratch the iron.