Vintage T-shirts are not only fashionable, but they're comfortable as well. Many new T-shirts from the store come crisp and a little bit stiff. It may take many washes and wearings before a shirt gets "broken in" and begins to look worn out, or vintage. However, there's a method that can speed this process up, and make brand new T-shirts look and feel vintage. When turning your new T-shirt into a vintage shirt, be sure to buy one that's a size larger than what you normally wear, as it will shrink significantly during this process.
Add 1/4 cup washing soda and 2 cups iodized salt to a bowl, and mix.
Set your washing machine to its hottest temperature and turn it on. Add your T-shirt. After the water level has risen to the top, add the salt/washing soda mixture you created in Step 1.
Dry the shirt in your dryer on high heat.
Make another smaller batch of salt/washing soda mix (keeping the same 0.25:2 ratio). Repeat the entire process three to five times, drying on high heat after each wash.
Use sandpaper to rub away little bits of any logo that the shirt has. This will help make the shirt look even more worn out. Use light, circular motions when sanding, but keep the strokes irregular for a more authentic aged look.