Achieving the perfect shade of blonde is never an easy feat.  The blonde spectrum is extremely wide-ranging, but whether you go for platinum white or dirty ash, the one colour you DON'T want is yellow. However, as time goes on, many blonde beauties notice their golden tresses developing a brassy tone, and it could be down to this very simple mistake - washing your hair every day. Speaking to Refinery29, Joico celebrity colorist Denis De Souza, who’s worked with the likes of Olivia Wilde, Kate Mara, and Jenna Dewan, explained: “Hair becomes yellow (lighter blondes) or brassy (darker blondes and brunettes) because of many factors, but it all starts with the frequency of the hair washes." [caption id="attachment_260197" align="alignnone" width="566"] Pretty beautiful woman washing her hair in a shower, close-up.[/caption] “The more you wash the hair, the faster it tends to go yellow or brassy, as shampooing tends to strip the color pigments.” This is partly due to the minerals and metals in your shower water, so one way to combat it is to purchase a shower filter. However, a much simpler way to avoid premature discolouration is to avoid the temptation to wash every day, and try to skip at least every second day, using a dry shampoo instead. Now go forth and shine, blonde bombshells. Hat Tip: Refinery 29