In 1879, James Norris Gamble developed a white soap. Harley Procter gave it the name Ivory, lifted from a line in Psalm 45 about ivory palaces, and later hired an independent lab to show it was purer than castile soap. By 1895 the slogan in use was 99 and 44/100 percent pure. That, more or less, is where American advertising decided that clean and pure were the same thing, and we have been smelling for it ever since.

Clean perfume is a phrase that now covers three separate ideas. It can be a brand, CLEAN, which its founder Randi Shinder started in 2003 because she wanted a fragrance reminiscent of pure soap, that universal fresh-out-of-the-shower smell. It can be an ingredient standard, though there is no legal definition of clean in fragrance, so each retailer and brand sets its own. Or it can be a scent family, the soapy, laundered, skin-close musks. I find it easier to shop once you decide which of the three you mean, and to read the brand's own definition instead of trusting the word on the box.

The trick is to start where the idea started. The CLEAN Reserve line is the brand's farm-to-fragrance collection, and PopSugar notes it is designed to be layered and gentler worn alone. Warm Cotton, with bergamot and musk, is the laundry-day one, built around aldehydes, mint and a musky, incense-touched dry down. Skin is creamy Madagascar vanilla and close-to-the-skin musk. Rain and Acqua Neroli are the two fresh, watery names, and Sun-Kissed Papaya with sandalwood is the sweeter, more playful choice. I would test them on paper first, and then on skin, before deciding.

A skin musk only tells you the truth about an hour after you spray it. Leave your wrist alone, then come back and smell it as if it belonged to someone else. If you would lean in to sniff a stranger, buy it. If it fades to nothing, it is a shower gel.

Maison Margiela does this family better than most, and the three here are quite different. Fit of Folly is a Scentsorium parfum with bergamot and musk, the most grown-up of the three. Lazy Sunday Morning is the laundry-line one, and Bubble Bath is exactly what it sounds like, both from the Replica range. Glossier's You Doux is the soft, close one for people who wear a fragrance mainly for themselves, and PHLUR's Soft Spot has a similar warmth in a friendlier bottle.

AERIN's Amber Musk is the fuller, warmer choice, better for evenings than mornings. Fugazzi's Cloudh Nine brings musk and oud, so it is the least soapy one here, but a good next step if you like a musk with a bit of edge. Cyklar's Bergamot Bond is a roll-on perfume oil with musk, which is the one I would drop into a tote for the afternoon.

Cyklar's roll-on on your wrists and a Reserve spray on your clothes works nicely, since the two behave differently on skin and fabric and do not compete.

What I would skip: heavier musks on a packed morning train. Save them for the evening.

Nobody expects a body mist to last all day, and that is half the charm. Keep it in your bag and use it after the gym, before a meeting, or on the way out.

Truly's Clean Girl Perfume Mist is the name that says the most about where this trend is. Saltair's Fine Fragrance Body Mist is the easy daily one. Herbivore's Coco Rose Coconut + Tremella Milky Body Mist is the softer one, and Vacation's Body Mist is the light, holiday-minded one. Byredo's Gypsy Water Body Mist is the grown-up choice, a lighter way to wear a name you may already know. NEST New York's Balinese Coconut Body Mist is the easy holiday pick.

AKT London's The Haze in Columbia Road is a deodorizing body mist, which is a different job and a useful one. Fenty Skin's Hey, Bouquet Allover Body Mist is the floral one, made for spraying all over.

Try this: spray a mist on damp skin right after the shower, then again in the same spot once you are dressed. That gives you a soft base and a bright top, and it lasts longer than a single pass.

What I would skip: a coconut mist on a hot day in a crowded room. Sweet scents get louder in the heat.

Scent sticks around longest when the wash, the cream and the spray share a family. Layer them and it stays on your skin without any of it feeling loud.

Cyklar's Naked Neroli body cream with niacinamide pairs neatly with the brand's roll-on, and AERIN's Amber Musk Body Cream is the same idea in a richer form, and it matches the Amber Musk perfume from the grid above. Josie Maran offers two, In Bed with whipped vanilla milk and cashmere musk, and Golden Hour with amber and white musk. By Rosie Jane's ROSIE body milk with white musk is the lighter texture, and OUAI's St. Barts Moisturizing Body Cream brings a little holiday into the bathroom.

Philosophy's Fresh Cream Warm Cashmere Hydrating Shower Gel begins the layering in the shower, which is the step people forget. Chanel's Coco Mademoiselle Moisturizing Body Lotion is the finishing touch if that perfume is already on your dresser, and I would happily give it as a present.

The shower gel and the body cream from the same family make a fine pair, then nothing on top at all. Some days the layers are the whole perfume.

What I would skip: matching the lotion to a perfume you have not worn yet. Test the scent first.

To me, the best clean perfume is the one that smells like your own skin on a good day, not the one with the most convincing label. Ivory sold us purity, but what most of us actually want is the smell of being fresh from the shower.

So I would begin with CLEAN Reserve Skin or Warm Cotton, add one body cream in the same family, and keep a small mist in my bag. Ivory had its slogan. A good musk needs none, because you only smell it when someone leans in. If you want to keep browsing, I also put together Light Blue Perfume and philosophy Perfume.