Next time you visit the salon be sure to ask your stylist for a cool-toned blonde. “Be very specific about what you don’t want (i.e. no yellow or warm tones). Ask for ashy, cool colours and avoid shades like caramel and honey, as they tend to run a little warmer.” Says Mitra. Once a week use a toning mask to keep any warmth from returning. Try Christophe Robin’s Shade Variation Mask in Baby Blonde, £16, it works for lifting subtle warm tones or neutralising full-on yellow hair disasters. Brassiness can happen right after you highlight your hair, or it can creep in gradually in the weeks and months after bleaching.

You can apply the toner to only the highlighted sections, or you can choose to put it on your entire head. Use the application brush to spread the toner over strands of your hair, starting at the roots healthy hairstyles to sleep in and working your way down. Look at the color chart and pick the level you’d like your highlights to resemble. Make note of what level it is so that you don’t forget when you go to pick out your toner.

If your hair is compromised, you should opt only for a semi-permanent hair dye to fix the issue. It deposits your selected color on your hair after mixing. To mix with the toner, purchase a 10 volume developer.

Reintroduce moisture into your hair through hydrating products. This can include natural oils, such as almond, organ, olive, or coconut oil. Applying even a few drops to your hair can help, as can deep-conditioning treatments.

DpHue’s Cool Blonde Shampoo and Conditioner is another favorite duo of hers. According to London-based colorist Leanne Chadwick, there’s a reason those at-home hair dyes that come in a box can be so fickle. It mostly comes down to the developer, the part of the dye that opens up the hair follicle so that pigments can penetrate them.

The way you treat your hair after coloring it can have a major impact on the longevity of the color. Never wash your hair with hot water after coloring it. Since coloring can dry out your hair, apply a conditioning mask to moisturize and nourish it.

You can spot paint or put over the whole head, but it will make the parts already painted more opaque or saturated,” says L.A.-based hairstylist Jill O’Neil. Instead, she says the best way to gently fix a hair color mistake is to use a clarifying shampoo, like Kristen Ess’ Deep Clean Clarifying Shampoo ($12, Target). “Using a clarifying shampoo once or twice a week will help break down the color molecules, making your hair fade faster.