Elderly Blue-Haired Lady

"Now the goose is on the table,
And the pudding made of fig, ahh,
And the blue and silver candles
That would just have matched the hair in Grandma's wig."

—Elmo & Patsy, "Grandma Got Run Over by a Reindeer"

Grey hair has often been considered a sign of respectable old age. Unfortunately, not everyone becomes a Silver Fox with age: those with one or two MC1R variant alleles will instead find that their hair turns an ugly dirty yellow. Older women in the 1970s 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 - 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", used in the 70s and 80s to describe older women in general (and still used in 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).

Not to be confused with the intensely blue hair of some anime women. Or men.

Examples of Elderly Blue-Haired Lady include:

Film

The violent old lady in the Madagascar movies is codenamed 'Bluehair' by the penguins.

Literature

In Amelia's Notebooks, there is one occasion where the titular character zones out in the lunch line and almost mistakes an elderly cafeteria worker for one of her troll dolls due to her blue-tinted hair.
Aunt Beatrice from The 39 Clues.
By the end of Auntie Mame, the titular character's hair "which had all gone to gray, was rinsed to a delicate periwinkle blue". Her great-nephew notices this:

She pressed her nose against Mike's and looked into his eyes. "I've never seen hair the color of yours, my little love. It's so red!"
"I've never seen hair the color of yours, either," Mike said. "It's ... it's so blue!"

Live Action TV

Dorothy from The Golden Girls isn't quite blue-haired, but she's close.
Mrs. Slocombe from Are You Being Served often dyed her hair some odd color nearly every episode. Usually, it was blue.
Phyllis Pearce in Coronation Street.
Briefly, in an episode of iCarly, there was a green-haired old lady (who sucks on a baby pacifier).
Thelma Harper from Mama's Family, who was once even referred to as a "blue-haired old dragon" by her daughter-in-law.
Grandma Yetta from The Nanny.
Conversed in Buffy the Vampire Slayer when Willow describes her future self as "old and blue-haired".

Music

Referenced in "Grandma Got Run Over by a Reindeer" by Elmo & Patsy.
In Ray Stevens' "A Little Blue-Haired Lady", the narrator is stuck behind one who is driving 20 MPH on the interstate.
Invoked in "We are Dead" by Dale Gonyea:

Do not wait to be a grandmother to have blue hair.

Web Comics

David Morgan-Mar states that he deliberately changed Jane Goodall's hair to that color.

Western Animation

Agnes Skinner, Seymour's "beloved smother—I mean, mother" from The Simpsons.
- Although it's worth noting that blue is a natural hair color in The Simpsons, so it might not be dyed.