The blade of a good meat cutter is made of high-quality stainless steel, and I can't guarantee anything else. Rust can be wiped off with fine sandpaper. If the dark place is not serious, it will not affect the use. When they are ready for use, they will naturally wear off, and then they will be washed with clean water. After they are completely dry, you can apply some oil to the surface, and be careful to put them in a dry place, otherwise they may rust.