Even if you don’t feel dirty, the world you move through collects on your skin, slowly adding layer after layer of invisible grime.

“During the course of the day, all of your environment accumulates on your skin — pollution, dirt, sweat residue, and any airborne particles or debris,” says Jenni Holman, MD, a dermatologist and Mohs surgeon at U.S. Dermatology Partners in Tyler, Texas.

On top of that, you shed up to an estimated 500 million skin cells each day, so those shedding skin cells are also accumulating on your body, says Dr. Holman.

That may sound a little gross, but it’s also normal. Skin is meant to have oils, bacteria, and shed cells on it; the goal of showering isn’t to scrub yourself sterile. It’s to wash away the excess buildup from the day — especially sweat, odor, visible dirt, pollen, pollution, and product residue — without damaging the skin barrier that helps keep moisture in and irritants out.

There’s a lot of buildup all over your body that you might (or might not) be able to see or smell. But it’s there.

Skin Oils Your skin cells naturally produce oil (sebum) to keep your skin barrier flexible and protected. That oil can mix with sweat, dead skin, dirt, sunscreen, makeup, and pollution. On oilier areas, such as the face, chest, back, and scalp, that buildup can contribute to clogged pores or a greasy feel.Sweat Residue Sweat itself is mostly water, but it also leaves behind electrolytes like sodium and other compounds as it dries. In warm, covered, or high-friction areas — such as the armpits, groin, under the breasts, and between skin folds — sweat can mix with bacteria and contribute to body odor, irritation, or breakouts.Dead Skin Cells Your skin is constantly renewing itself, and old cells naturally shed from the surface. Most of the time, this process happens without you noticing. But dead skin cells can build up and mix with oil, sweat, and products, leaving skin feeling rough, flaky, or dull.Pollen and Allergens Your skin and hair can carry pollen indoors after time outside, especially on dry or windy days or after yardwork. If you have seasonal allergies, this can lead to issues like sneezing and watery eyes.Germs Many bacteria and other microbes normally live on skin, and that’s not automatically a problem — in fact, a healthy skin microbiome is important. But some germs are harmful, and if they move from your hands (for instance) to your mouth or eyes they can cause illness.Pollution Residue Tiny particles from vehicle exhaust, smoke, industrial pollution, and other environmental exposures can settle on the skin. Pollution can contribute to oxidative stress and inflammation, and may worsen dryness, irritation, acne, eczema, psoriasis, or rosacea in some people.Product Buildup Sunscreen, makeup, deodorant, bug spray, body lotion, and hair products can all leave residue behind. That doesn’t mean they’re bad — sunscreen, in particular, is essential — but they can cause skin issues over time if not removed.

For most people, daily cleansing is typically enough for normal skin, says Holman.

Generally, the basics work: lukewarm water, a gentle cleanser, and a shower that doesn’t go on too long.

“As a dermatologist, we typically recommend gentle soaps, as we are seeing patients with impaired skin barriers,” says Holman. Fragrance-free soaps or soap-free cleansers will remove the accumulations of the day without weakening or stripping the skin barrier, she explains.

And keep in mind “natural” and “gentle” aren’t the same thing, she says. “Poison ivy is as ‘natural’ as it gets but not gentle,” says Holman.

After showering, pat your skin dry rather than rubbing hard. If your skin is dry or sensitive, apply a gentle moisturizer right away while you’re still slightly damp “so that evaporation of the water doesn’t leave skin more dry or impaired,” says Holman.

Your face has different cleansing needs than the rest of your body, so you may need to add an extra step if you’re washing off everything in the shower.

“Sometimes you need a different cleanser for your face; people often wear daily sunscreens or makeup and need a stronger cleanser to remove these,” says Holman.

“Our skin is naturally covered in bacteria, shed cells and proteins, and environmental particles,” Holman says. But that doesn’t mean it’s a good idea to go about your day like Pig-Pen from Charlie Brown. “If your skin is visibly dirty, clean it,” she says.

Some people may also need medicated or condition-specific cleansers for acne, rosacea, seborrheic dermatitis, or other skin conditions, says Holman.

If your skin is persistently itchy, cracked, burning, flaky, inflamed, or easily irritated, it may be a good idea to see a dermatologist, says Holman. The answer may not be showering more — it may be finding a gentler routine that protects your skin barrier while still getting you clean.

• Your skin collects oil, sweat residue, dead skin cells, pollen, germs and pollution throughout the day.

• A gentle, fragrance-free cleanser and lukewarm water are usually enough to wash away daily buildup without stripping your skin.

• Focus soap on sweaty, odor-prone, or visibly dirty areas, and use a separate face cleanser, especially if you wear sunscreen or makeup.