Got leftover lemons? Give your white T-shirts a good cleaning. The natural acid in lemons can help brighten and freshen cotton fabric. And if your white T-shirts have stains on them from sweat or deodorant, lemons can help remove the stains for good. Just rub salt and cut lemons all over the fabric where you have a stain. Let it sit for a few minutes, then rinse before laundering for fresh, clean, stain-free shirts.