How to test the material of stainless steel foster cage?

Simply put, we can use stainless steel determination potion for its detection, there is a universal stainless steel detection potion, just use a dry cloth or paper towel to dry the surface of the foster cage, and then a drop of the detection liquid, and then observe its color change, the point of the liquid after the time should be strictly controlled.

(1) 301 stainless steel foster cage, droplets in 30 seconds, turning light red.

(2) 304 stainless steel cage, droplets in more than 50 seconds slowly turn light gray.

(3) 201 stainless steel cage, the droplet instantly (1 second) turns into brown color;

(4) 202 stainless steel foster cage, the droplet turns brownish red in about 15 seconds;