1. Sunshine exposure method

In a sunny life, use a screwdriver to remove grease and then fly to 45 degrees. Compared to the sun, observing the condition of the droplets, it is excellent to clearly see that there are no debris in the lubricating grease under sunlight, which can restore its effectiveness. However, if there are too many debris, the lubricating grease must be replaced.

2. Droplet imprint method

Take a clean white filter paper. If a few drops of oil leak from the filter paper and there is black powder on the surface after the oil leaks, there will be resistance when it comes into contact with hands, indicating that there is a lot of residue in the oil, the oil is not powdery, dry and clean, and the imprint is light yellow.

3. Oil discharge observation

Take two beakers, one filled with grease for inspection and the other empty on the table. Remove the beaker containing oil from the tabletop by 30 to 40 centimeters and tilt it to allow the grease to flow into the empty cup and observe its fluidity. High performance and cost-effective lubricating grease should be long, thin, uniform, and continuous. If the oil is discharged quickly and slowly, it means that the oil is moldy.

4. Hand twisting method

Twist the grease between the thumb and ring finger and continue grinding. Good oil feel, good wettability, minimal wear and debris, and no friction. If you feel a lot of friction between your fingers like sand particles, it means there are many residues in the oil and it cannot be reused. Replace with new lubricating grease.