If the silicone oil is not preserved properly, it is easy to deteriorate. So, how do we distinguish?

1. Hand twisting. When the dimethylsilicone oil is twisted between the thumb and the index finger for repeated grinding, the hands with better quality feel lubricity, less wear debris and no friction. If the greater friction feeling such as sand grains between fingers is felt, it indicates that there are many impurities in the oil and can not be used again, so it should be replaced.

2. Oil drop trace method. Take a clean white filter test paper, drop oil several times on the filter test paper. After dimethylsilicone oil leaks, if there is black powder on the surface, if you touch it with your hand, it means that there are many impurities in the oil. If it is of good quality, there should be no powder, and it should be dry and smooth with your hand, and yellow traces.

3. Oil flow observation method. Take two measuring cups, one of which is filled with dimethylsilicone oil to be inspected, and the other is empty on the table top. Lift the measuring cup full of oil 30-40 cm away from the table top and tilt it to let the oil flow slowly into the empty cup. Observe the flow situation. The good quality should be slender, uniform and continuous. If the oil flows fast and slowly, and sometimes large pieces flow down, it is said that it has deteriorated.