Check if your hair is healthy enough to withstand bleaching.
Perform a strand test before starting.
Mix a small amount of the bleach powder and liquid peroxide per manufacturer's instructions.
Dip the strands into the bleaching mix so that they are completely saturated.
Set a timer or keep track of how much time passes during the test.
Every five minutes, check the strands by wiping away the bleach with an old cloth.
Reapply the bleach again, and repeat the process until you have the desired shade of blonde. Now you know how long to leave the bleach in your hair.