I can't attest to this but I've read that soaking hands and nails in denture cleaner (like Efferdent) for a few minutes will bubble the dirt off of hands and out from under nails. Anybody tried it? There's also a commercial product called Bubble White which is similar but more expensive. I've tried it and it does work well.
http://www.sallybeauty.com/on/...
Another favorite product is pretty feet and hands. It removes rough, dry, skin with embedded dirt from your hands
http://www.prettyfeetandhands....
Karen