Try to find a delicate towel or cloth, maybe something with micro fibers. Put just a small amount of water on the cloth, maybe the size of one or two dimes. Begin wiping down your iPhone, especially the touch screen. While going over it remember to be exceedingly gentle, and focus more on the wiping across the surface instead of applying pressure. Try to avoid the ports where peripheral or connection devices plug into the phone. Once it has been thoroughly wiped down use the dry part of the towel you have been using to go over the device again until it is fully dry. Try to do this process as often as possible.