These are caused by oils and fats. They are the most deceptive because they are initially difficult to spot on dark fabrics.

• To the touch, they leave the fabric feeling soft but slippery, and almost transparent when held up to the light. They often darken the fabric’s weave. Over time and when exposed to heat (e.g. an iron), they tend to set and turn yellow.
• Typical examples: Cooking oil, butter, make-up (foundation, lipstick), mayonnaise, sebum from the neck or cuffs, seasoned tomato sauce.

These are caused by organic substances that are sensitive to heat.

• If they dry out or are soaked in hot water, they become stiff and crusty to the touch. They often change colour, turning a shade of brown or grey.
• Golden rule: Never wash them at high temperatures before treating them, otherwise the proteins will denature and become permanently bonded to the fabric fibres.
• Typical examples: Blood, eggs, milk, ice cream, sweat, food residues or baby food.

These are caused by natural pigments found in plants, fruit or drinks.

• They have very intense, distinct colours (red, purple, dark brown, bright yellow). They do not alter the texture of the fabric to the touch (they are neither sticky nor stiff), but penetrate deep into the fibres.
• Typical examples: Red wine, coffee, tea, fruit (cherries, blueberries), grass, beer, soya sauce.

These are caused by external artificial agents or body care products.

• They often have a distinctive, pungent chemical smell. They can permanently bond fibres together (like glues) or directly discolour the fabric (like bleach).
• Typical examples: Pen or marker ink, paint, glue, deodorant (the typical hard, whitish or yellowish stains under the armpits), mud or soil.