Breathe a sigh of relief: your shampoo and mouthwash are legal again. Last week the Transportation Security Administration loosened its carry-on ban on liquids, allowing travelers to bring some toiletries on domestic flights. (International policies vary, so check with your airline.) But here's the catch: you've got to pack the toiletries in a clear plastic one-quart zip-lock bag. If your bag is too big, or if you have more than one, you'll likely be sent back to the checked-luggage counter. Also, remember that none of your toiletries can be stored in containers larger than three ounces--including aerosol cans, which are allowed now, too. The restrictions don't apply to baby formula or prescription medicine. For a complete list of what you can and cannot pack, see tsa.gov . Or just ship your luggage ahead.