I use this product from J.R. Liggetts http://secure.jrliggett.com/proddetail.php?prod=2005 This is all natural and does not leave any soap residue and gets everything very clean. Also, this is a really great shampoo for everyday use. I have not used regular shampoo in over 3 years as this is the best that I have found! You can also buy this on Amazon as well if you only want a single bar or so. I carry only a single bar and use that for both shampoo and hand washing clothing. Since it is a solid it has not been an issue so far with TSA.