New shirts sometimes arrive with a crisp, starchy texture, typically caused by factory chemicals or a rigid fabric fiber. Not only are these shirts uncomfortable, but they can also drape in unnatural shapes and show unusual wrinkles no amount of ironing will remove. Clothing often takes years of regular washing and wearing to soften up and mold to the body; however, loosening up the fibers early can create a softer, more natural wear faster.
Spot test a drop of vinegar on an inside hem. Rinse the spot under the faucet and wait until the shirt dries to see if the color changes. If so, do not use vinegar on this shirt.
Fill a gallon bucket with warm water. Measure 1/2 cup of salt in a measuring cup and pour it into the water.
Mix the salt water with a wooden spoon and add the shirt. Let the shirt soak in the bucket for up to three days. Some dark dyes may bleed into the water, but this is natural, as salt typically draws out excess dye during the initial dyeing process.
Move the wet shirt into a washing machine. Fill a liquid measuring cup with 1/2 to 1 cup of white vinegar and pour it into the machine. Add 1 tablespoon of baking soda.
Run the washing machine on a cool water cycle. Although hot water is better at softening fabric, it can also cause unwanted shrinking.
Add the shirt and a softening dryer sheet to the clothing dryer. Run the dryer on a low-tumble setting. Once dry, iron the shirt without starch.
Repeat the process if the shirt is still not soft enough. This time, soak the shirt in a vinegar bath for three hours instead of a salt bath for three days, and add no vinegar to the washing machine cycle.