The present invention teaches methods and apparatus for extending the life of an x-ray tube. An x-ray tube typically contains an insert for generating x-rays. The insert is housed in a housing wherein an insulating fluid circulates around the insert in the housing to provide thermal and electrical insulation. The present invention includes methods and apparatus for removing water from insulating oil. One embodiment of the invention includes a processor containing a coalescing element for removing water as a vapor from the oil. Other embodiments include methods and devices for drying the interior of the housing. Another embodiment of the invention includes a kit containing a processor having a coalescing element for removing water from the insulating oil. The portable kit allows the invention to be practiced on x-ray tubes maintained in gantry supports of x-ray machines, such as CT scanners.