NOTICE: Before the clippers leaves the factory, the sharpness of the Bladeds Head will be tested. Use black cotton thread to simulate human hair for cutting. If you receive a clipper with black lint on the Bladeds Head, this is just a test residue. The product is brand new. In the cleaning process, the Bladed Head can be washed, and the machine body can not be washed. For safety, please take care of the skin near the ears when shaving. If the trim is poor during use, please first clean the hair in combs and Bladed.