I used to live about 10 miles west of a paper mill in NC. Our prevailing winds are west to east. If it was a cold damp day in the winter and you smelled the paper mill, you knew you were going to get snow sometime soon.Smells can also trigger negative memories.
Old cat litter
Decomposing body or carcass
Those with positive memories (some already posted)
Freshly ground coffee
Just fired shot shell hull
Africa in burning season
Vanilla makes my mouth water.The smell of a slough hay bale when you roll it out in the winter. And of course the cows.
Also the individual smells of my local game animals. Whitetail, mulies, pronghorn, moose, elk and black bear all have their unique aroma that you can identify blindfolded.
I have the same memories of the smell of spent shotgun shells, but from the 50’s. Those old 10 gauge paper hull, old powder loads of Dad’s had a smell all their own. Nothing like plastic hull newer powder shells of today.Every single time I smell a freshly fired shotgun shell it takes me back to 1973 when I was 4 years old. Dad would stick me and my younger brother behind him in the weeds when he was duck hunting. His empty shells would end up back there with us and I loved the smell of them.
Good memory, I had forgotten about that. Very distinctive smell. Ovepowered little buggers those engines were and are! The ultimate 2 stroke. I think mixture of methanol (alcohol) and castor oil. Some types with a dash of nitromethane added for evenness of burn- IIRC same function as octane regulation in gasoline engines. Thanks for rememberingOne of those little engines firing up on the model aeroplanes we used to build, a tiny little thing called a Cox Baby Bee if I recall.