DIY shapped soaps for kids

My kids come in filthy from playing outside and if I can do something that makes them WANT to get into the bath/shower....I'm gonna try it. Here is the next items on my try list (mainly because I scored the FREE Ivory soap recently using my $1 off coupon from the sunday paper). What you need is a bar of Ivory soap, a plate, water, a food processor, cookie cutters or silicone candy molds, a microwave, and little helpers.
What you need to do first is unwrap the bar of soap and place on a microwave safe plate. Nuke for ~3 minutes. The soap will become big and "fluffy". At this point and adult should carfully handle the soap and check to be sure it is a safe temperature before handing over the little hands. Once safe, little hands can crumble the soap "foam" into the food processor for you. Close the food processor and drizzle a little water into the mixture until it blends together like a pie crust would. Once blended, open the food processor and remove the blade. Now allow the children to take the mixture and pack it into the cookie cutters, filling generously. All the formed shapes should be allowed to dry before use.
Put dried soaps into a open container and allow them to pick one for their next bath/shower. How fun!