New denim looks crisp and clean, but it can also feel stiff and uncomfortable. If you don't like your denim to feel stiff, you can soften it before you wear it. Repeated washing can soften denim, but without an added boost it may take weeks of washing to get the desired effect. Fortunately, you can expedite the process by adding vinegar to your washing machine because the acid in vinegar breaks down the fibers of the fabric, giving them that "already- worn" feeling. Best of all, vinegar helps to maintain the color of your denim so it won't fade during the wash cycle.
Set your washing machine to a small load, as you should only wash between one to three denim items per load when you are trying to soften them. Set water to cold or lukewarm, as hot water fades denim.
Add an appropriate amount of laundry detergent for your load size as the washing machine is filling. Add 1 cup of distilled white vinegar.
Turn your denim items inside out. Submerge the denim in the water-filled washing machine drum.
Allow the washing machine to run through until it gets to the rinse cycle. Add double the amount of liquid fabric softener as is recommended for your wash load size.
Remove your denim from the washing machine. Shake the denim items out to remove twists and wrinkles. Tumble the denim dry on medium-low heat to prevent shrinking.