There are many different ways that you can take to starch jeans, but the most common is to wash your jeans before you take them out of the dryer.
Once they’re completely dry, grab a dish towel or two and throw them in. Next, pour some hot water over the jeans and cover them with an old pillowcase or sheet.
Now all you have to do is wait for about ten minutes for the water to soak through the jeans. Pour out the water and remove the pants from the dishcloth or sheet, then hang them up to dry again. Once they are dry, the pants are ready to wear.
Note: This method is for darker jeans that aren’t too light or thin. If your jeans are thinner, they might be best washed by hand in a sink or bathtub with cold water and laundry detergent.
So this is how to starch Jeans.