Abstract: Method and apparatus for producing and recovering solvent vapor for cleaning the interior surfaces of substantially sealed vessels and the exterior surfaces of structures contained therein]. In the illustrated embodiment, a transportable vessel cleaning system is disclosed. The system comprises a plurality of solvent vapor producing chambers, each having a solvent vapor outflow port and a solvent vapor inflow port coaxially arranged along a vapor flow axis extending through each chamber along flow channels associated with the solvent vapor outflow and inflow ports. When operationally configured with a substantially sealed vessel, each solvent vapor producing chamber of the present invention produces a solvent vapor stream which is recirculated through the vapor delivery tube, vessel interior, vapor recovery tube and the solvent vapor producing chamber along the direction of its vapor flow axis.