Two ways to identify a stain are:
(a) By smell
(b) By feel
( c) By colur
Procedure of removing unknown stain from white cotton kurti is as follows:
(a) Soak in plain water
(b) Soak in warm soapy water
(c) Bleach the stain by exposing to sunlight
(d) Treat with dilute alkali
(e) Treat with dilute acid
(f) Apply oxidizing bleach