Salabrasion is a form of dermabrasion tattoo removal. Which is the older and brutal procedure for removing a tattoo. A wet cloth or piece of gauze is dipped in salt and then vigorously rubbed over the tattoo until the entire area turns a deep shade of red.
A good analogy is to think about using sand paper to sand away at the skin until the layers are scraped off. It basically involves scrubbing your skin raw using granules of table salt.
A rotary like tool may also be used to more effectively peel away the skin and pigments. Basically, the area is rubbed until it is raw and it will certainly require bandaging afterward.