Best of all, the manufacturer has several great kits which are geared towards girls. If you have a daughter who longs for a spa day, then get her the Spa Science Kit - she'll get to make her own spa treatments by mixing (safe) chemical and ingredients. There are even bottles and labels so she can make her own products to give (or sell) to friends and family. The Spa Science Kit is super hands on and super fun and will make your daughter think in a whole different way about what is in her bottle of shampoo.
With regards to your spa bachelorette parties, a salt scrub can be used to the wrists and hands also; get an adequate amount in the palm of your hands, apply quickly together, over the surfaces of the two and along every fingernail. Wash off and take a look at exactly how gentle and smooth both hands became.