(a) Colour: Every stain has a specific colour, for example, curry and pickle are yellow while coffee and tea stains are brown, and grass stain is green.
(b) Smell: Some stains have a peculiar smell eg. Stains of eggs or paints. These stains can be recognized by the smell.
(c) Feel: Some stains also change the feel of the fabric and can be recognized on that basis. For example paint or sugar syrup makes the fabric stiff to touch, whereas lipstick or shoe polish make the fabric feel slippery.
