Fan Casting Elderly Blue-Haired Lady in Sort by Tropes

Grey hair has often been considered a sign of respectable old age. Unfortunately, not everyone becomes a Silver Vixen with age: those with one or two MC1R variant alleles will instead find that their hair turns a shade of yellow which many find unappealing. Older women in The '70s and earlier who wanted to be gracefully grey would therefore get their stylists to treat their yellowing hair with a blue rinse, which, with luck, would tone down the yellow and leave a silver grey. It didn't always work — for not everyone's hair absorbs the same amount of dye — and many older women walked around with distressingly blue hair. This led to this trope and also to the phrase "the blue rinse set (or brigade)", used in The '70s and The '80s to describe older women in general (and still used in British politics to describe old Tory women who don't think women should participate in politics and make sure that happens by taking control of local branches of the Conservative Party).