Toner is nothing but color that you put on your hair after a highlight job. Toner uses extremely low developer to gently change the tone of hair color and turn bright highlights into a more flattering hue. Toner should not dramatically change the color; it should just tweak it a bit. Always use 5-volume developer with a toner application to gently push the tone of the color into the hair shaft without using an excessive amount of damaging chemicals.
Sometimes highlights turn out a little bright. If canary yellow or orange wasn't the look you were going for, tone it down with any color possessing the opposite color base. Think of the color wheel you used in art class. Colors directly across from each other on the wheel cancel each other out. So blue- and violet-based colors would cancel yellow and orange.
Smoky tones happen when the hair possesses too much blue or violet tones. How can you fix it? Add more warm tones to the color. Use toner that has an orange or yellow base to counteract the smoky, grayish color. If you want the gray look, use more blue or violet to enhance the color.
Strawberry blonde, caramel and golden blonde all happen when toners that enhance colors, rather than correct colors, are placed on the hair. Toners of certain base colors enhance hair color so that it appears more red, as in the case of strawberry blonde. Caramel uses orange tones and golden blonde uses gold tones.
Toners are color. You can go to the beauty supply store, pick up any bottle of color, mix it with 5-volume color developer, and you've got toner. But toner can get a little wacky if you try to do too much with it. Do not try to darken or lighten your highlights with toner. Always use a toner with the same level of darkness or lightness as your hair.