Ooooh! I had forgotten the smell of the purple pages. Mmmmmmmmm
ETA: Looks like I’m thinking about spirit duplicators, or the “ditto machine”. Either way, mmmmmmmm.
The smell of paper when it comes out of the printer.
The smell when you open up a vinyl record.
- The hot dust smell of the heat going on for the first time in the fall/winter
- a horse barn on a rainy day
- a load of new hay
- snow in the air
- strong black tea, scalding hot
- books that have been packed in a box for a long time
- tiny baby kittens, less than a month old. Better than puppy breath
Johnson’s Paste Wax. My mom used it on the floors of our first house.
The local store in the town where we spend summer vacation has wooden floors. It’s tiny, but you can get everything you need there. 
Lighter fluid
My grandpa had a leaky old Zippo lighter that he kept in his tackle box. That smell meant going fishing with Grandpa
Oh, lighter fluid! Perfume of the gods.
Snow. I swear, I can smell and also taste snow. It’s very subtle. Love opening the door in the overheated house and breathing deep, with the scent of snow.
Rubber bands-heavenly! and cedar shavings from a pencil. Absolutely enticing. I had some ‘cedar’ essential oil once and when I got some on my hands, would be sniffing them furtively all day.
I used to work at Ridley Mission Control Center, which was across the street from the ramp at Edwards AFB. I loved the smell of jet fuel in the morning.
.
- Diesel exhaust, because it reminds me of childhood trips to Disneyland.
- Cats.
- That weird burny smell that happens when you first fire up a new motorcycle.
- Bain de Soleil suntan cream (the old stuff they used to make in the '70s - it was fluorescent orange, and child-me would sneak it out of the cabinet so I could sniff it.
- The after-smell of Safeguard soap (open the box, take a big sniff, and then savor it.)
Thought of another one - chlorine. That smell is like an aphrodisiac to me.
Wow! Some of these descriptions are really evocative; the emotional details and memories that come from just reading responses points out that smell may be our most powerful sense for recall.
Brought to mind that I like the smell of old houses – including mine. A whiff of damp basement, old wood, and what is probably damp rot.
WD-40 oil.
Kiwi shoe polish in the little round can, especially black.
Ditto (hee hee) on the purple mimeograph ink. It’s a wonder my third-grade cohort isn’t brain-damaged from worksheet huffing.
I forgot one too - used book stores.
I distinctly remember emerging from the tunnel as I entered The Rock (Rockingham) and wondering what that funky smell was. One whiff (yes, even from the chainsaw) and I’m taken back to faster times.
RZ350… nice. I had one for a while but only rode it on the street. My 2-stroke race days were spent over an RD400.
WD-40
Tar
Chlorine
Laundry fresh out of the dryer.
Depression* food, e.g., hamburger hot dish or tuna casserole, made with Campbell’s cream of mushroom and cream of celery soups. My landlord is making something like it upstairs right now, and the smell just transported me back to my mother’s kitchen.
*The economic upheaval, not the emotional state,
The smell of freedom!*
*In more ways than one. 
Circus and carnival aromas: cotton candy, popcorn, candy apples, sawdust, gunpowder (from fireworks mostly), hotdogs, animals in exhibits, … others hard to identify from pure memory. Help!
Are you me? Those were the first 2 that came to my mind.
Moved this over to IMHO.
The question to determine if we are, indeed, doppelgangers:
As a child, did you love the smell of Mentholatum so much that you regularly ate it?