How to make a stiff t-shirt look and feel vintage - will shrink, so buy large: Wash 3-5 times in hot water with 1/4 c sodium carbonate washing soda 2 c salt (use smaller batch after first wash do not added directly onto shirt). Dry on high heat after each wash. Using fine-grit sandpaper, lightly swipe over logo in circular but irregular strokes.
My dentist actually told me about this. Use a little toothpaste, mix in one teaspoon baking soda plus one teaspoon of hydrogen peroxide, half a teaspoon water. Thoroughly mix then brush your teeth for two minutes. Remember to do it once a week until you have reached the results you want. Once your teeth are good and white, limit yourself to using the whitening treatment once every month or two.