2. Dissolve raw starch in a basin with cold water. Each shirt collar needs about 5- 10g starch and about 150ml water.

3. Fully dissolve raw starch in the well and stir it evenly. Immerse the shirt collar in starch water, squeeze it dry and spread it out repeatedly, so that the collar can fully absorb the starch in the water.

4. Dry the collar by hand, put it flat on the ironing table and iron it immediately. Be careful that the ironing temperature is not too high, and iron the front of the collar.

5. Fold the collar while it is hot, so that the two collars protrude outwards and are plump and symmetrical. So the collar stood up.

Note: if there is significant light after ironing, it means there are too many starch stars; If the collar is still weak after sizing, it means that the starch consumption is insufficient.