Simona
I'm using the rock salt and it helped me few times:
First Add Rock Salt to a mixer jar - take the rock salt and put it in the mixer grinder jar and switch it on. The rock salt should be in form of crystals and not powder to get the desired result.
Switch the mixer jar on and off Intermittently - remember that after some seconds of the interval, you switch the mixer grinder off. This is to add new lumps of rock salt and Take out the previous powder one. Then again turn it on.
Repeat Step 2 for around 10 minutes - keep repeating the process d for nearly ten minutes.
Wash the jar - once you are done with step 3, empty the jar. Then rinse it with water. Don’t worry you can use the powdered rock salt for your cooking purposes and there will be no wastage of that ingredient.
Your sharpened blades are ready- finally, the blades have been sharpened successfully without any hassle.