1. Magnetic Properties: Stainless steels are generally non-magnetic. That is, they do not stick to a magnet when brought into contact with a steel surface. Other types of steel, especially those with high carbon content, can be magnetic. However, this method may not always provide accurate results, as some stainless steels can be slightly magnetic.

2. Rust Resistance Test: Stainless steels are named for their resistance to rust. Therefore, if rust spots or corrosion marks appear on a steel surface, it means that the steel is not stainless. To perform a rust resistance test, you can drip water onto the steel surface and wait for a few hours. If rust spots or corrosion marks develop, the steel is not stainless.

3. Labels or Marks: Stainless steels often come with labels or marks indicating that the material is stainless steel. These labels or marks can provide information about the type of steel using a numbering or grading system specified by the manufacturer.

4. Chemical Analysis: The most accurate method for differentiation is chemical analysis. This involves analyzing a steel sample in laboratory conditions. These analyses are used to determine the steel's components and verify its stainless properties.

5. Appearance and Surface: Stainless steels typically have a bright, smooth, and shiny surface. The brightness and surface quality of stainless steels can be distinguishing features compared to other types of steel. However, this characteristic can vary depending on surface treatment and the grade of steel used.

6. Examination with a Magnet: The fact that stainless steels do not interact with magnets or show very little magnetism can help differentiate them from some other steel types. Stainless steels are non-magnetic or exhibit very weak magnetism. Therefore, if a magnet does not stick to a steel surface, it is likely that the steel type is stainless. However, these methods do not always provide definitive results, and in most cases, a combination of several different methods may be necessary. Especially when it comes to laboratory analysis of steel samples, consulting an expert is important for accurate results.