An improved vapor generator and control system includes a vaporization chamber for generating superheated vapor from liquid therein and at least one input connectable to liquid supply and adjustable control for controlling input of liquid into the vaporization chamber whereby output of superheated vapor is controllable while the system is in operation. A method for fabricating vapor generators includes the steps of providing at least two separate parts of a vapor generator, fastening the parts together to form a vapor generator defining a vaporization chamber and providing a capability to connect input control for control of input of liquid to the vaporization chamber. A method for cleaning selected objects comprises the steps of generating superheated vapor and controlling output of superheated vapor terms of volume and/or pressure and/or direction by adjustably controlling in an ongoing manner volume, pressure, and velocity of the liquid being subjected to vaporization. A method of propulsion comprises the steps of generating superheated vapor and adjustably controlling output of superheated vapor to provide propulsion.