A 1989 advertisment for Holeproof’s Antz Pantz underwear, which put the dated phrase firmly into the current venacular and sold a metric shedload of undies.
It’s actually the only line of dialogue in the ad.
“Hi guy.”
“MONAaa?!!”
“Out through the window was the way to the ground, the old lady took a last look around. The old lady knew just what to do.” “DO YOU??”
“I’m Inky, I’m Blinky, I’m Pinky, I’m Clyde! We’re the marshmallows you’ll find inside!”
Oh man. I hadn’t thought of that in forever.
I hated that guy’s adenoidal voice and northeastern accent.
Thank you. I think. 
The marketing pros monitoring this thread will be interested to note that ~50 years after that commercial was current I can instantly recall the scene w the two-sided medicine cabinet, hear the man’s irritating but memorable voice, and see the interior of their bathroom and what he was wearing.
The product they were selling? I have no clue except the trivial deduction it was a bathroom consumable. And that’s a 2024 deduction, not a 1970s memory. Unlike his irritating face, A-shirt, and crappy little bathroom.
This guy?
Ernie Von Schledorn! … 
Main Street in Menomonee Falls…
The only commercials I could find are from years later, after everyone was sick of the jingle, so they have people singing it, and Ernie (with a toned-down accent) just saying more “normal” lines.
But for a while, “Who d’ya know wants ta buy a car?” was everywhere. Even saw a sign outside a church in “M’waukee”:
“Whoja Know Wants Ta Go Tah Heaven?”
Easiest Google ever: Actor who sounds like Danny DeVito
On the contrary, LSLGuy. Cal Worthington and his various “dogs” were omnipresent on our TV channels in Alaska for the longest time.
And if we want obscure, consider:
"It didn’t break. It didn’t break ! "
Back from the days when Liquid Prell shampoo stressed that it came in a plastic bottle (and wouldn’t break if it slipped from your wet fingers).
Cal Worthington’s company had branches all over the west coast, and even in Houston, so we got his commercials even in New Mexico.
I can spot the Pittsburghers (aka Yinzers) with this one simple trick:
Century Three
Chevrolet
Lebanon Church Road
Pittsburgh…
Yep. That guy. You can almost see his adenoids hanging out from his nose. Gawd what an annoying voice. Just shoot him and put the rest of us out of our misery.
Hmm. So Right Guard is what they were selling. That feels totally familiar and obvious to me now but there is exactly zero point zero zero zero … percent chance I could have recovered that memory on my own.
Wow. Color me surprised and amazed. And edumacated. Thank you. I had not realized he’d branched out beyond SoCal.
I don’t remember the exact product (nor do I wish to), but 40-something years ago there was a commercial for a feminine hygiene product that played for maybe a month then was yanked off the air because of the tagline:
“Look for the box with the dots.”
The packaging had red polka dots.
Homer Simpson voted for them to go back to the old glass bottle. After that, he became deeply cynical.
I remember this but wasn’t aware of it being taken off the air. Now we get graphic simulations of blood saturated pads and Amy Schumer explaining about heavy and light flow days. Progress(?)
My obscure line - “the boer wars”
Someone made a store just for me…
I give up. I remember seeing him and his German Shepherd every Saturday when sitting in front of the TV, but never saw bothered to notice his name.
Pretty sure there would be a lot of local commercials with lines that would be immediately recognizable to people in the locality, but not necessarily to anybody else. Heck, for years, Toronto heard Mel Lastman and his son Blair tell us how “Nobody beats Bad Boy!” (A furniture/appliance store.) “Noooooo-body!”
Was it Dan Creed in Buffalo, NY, who told us to “Push, pull, or drag it in; we’ll take your trade-in”?
But the national ones. “Hi, guy!” and the bathroom mirror I certainly remember. There’s also, “I can’t believe I ate the whole thing,” and “That’s a spicy meatball,” and “Get good taste. Get Star-Kist.” Heck, I used to be able to do a pretty good Charlie the Tuna impression.
Can you do Phil Silvers?
We had a similar one:
Do like Stu and You’ll save, Too!
Push it.
Pull it.
Tow it to Golf Mill Ford!
Stu was a heavy fellow shown demonstrating those techniques named of dragging beaters for tradein.