Foundation on the collar and what removes it

Short answer: Foundation is oil and pigment. A little liquid dish soap applied directly to the stain before washing is the simplest solution that works every time.

The oil has to go first, always

Detergent alone often removes the pigment, but it rarely removes the oil that binds the foundation firmly to the fabric. A few drops of dish soap loosen the grease effectively, since it is made specifically to break fats down. See bamboo tops for women, which handle this treatment without any trouble.

Work it gently into the fabric

Massage the soap in with a finger using circular motions and let it sit for ten minutes before moving on. Do not rub with a brush or a hard edge, since that wears unnecessarily on the soft knit and can pull threads in the weave.

Wash normally afterward at the right temperature

Wash at 40 degrees as usual and check the stain carefully before the garment goes into the dryer afterward. The dryer's heat sets any remaining residue permanently, so a quick check before drying saves you from having to repeat the treatment. See bamboo t-shirt for women, which holds up well through many washes.

Prevent it with a scarf around the neck

Wrap a scarf or pashmina around your neck when getting dressed after makeup is done, especially when putting on outerwear. That is far quicker than removing stains afterward, and it also protects the collar from wearing out due to repeated contact.

Cold liquid over warm for stains on the go

If the accident happens while you are out, blot gently with cold water from a bottle rather than warm water from a tap. Heat can make the pigment more stubborn, while cold water keeps the stain more manageable until you get home to treat it properly.

Always test the product on an inner seam

Try the dish soap on a small, hidden part of the garment first if you are unsure how the fabric will react to it. Some dyed fabrics can turn slightly lighter where the product is applied, and it is better to find that out somewhere no one sees.

Foundation on several garments at once

If foundation hits both a sweater and a collar at the same time, treat each spot separately with dish soap before the whole garment goes in the wash. Do not rush the process, since thorough work now saves you from a visible mark later somewhere you cannot hide it.

Older, dried in stains need patience

A stain that has sat for several days can rarely be solved in ten minutes, so repeat the dish soap treatment two or three times. Soak the garment between rounds if you can, so the oil gets more time to loosen from the fibers.

Dresses need extra attention at the collar

Foundation often hits the collar of a dress harder than an ordinary sweater, since the fabric sits closer to the skin at the neck. See bamboo dresses, where the same dish soap trick works just as well as on other bamboo clothing, without the color or knit taking any damage from the treatment.