The invention relates to a method which comprises making a hole in a metallic support of an absorber tube, putting a vacuum pump in fluid communication with the chamber of the absorber tube by means of the hole, actuating the vacuum pump to generate a vacuum in the chamber until reaching a predetermined vacuum threshold, and introducing an inert gas inside the chamber and performing a plurality of sweeps with said inert gas, removing hydrogen from the chamber, allowing to thus reduce or remove the accumulation of hydrogen in said chamber, such that, as a result, at least part of the hydrogen absorption capacity of the getter material is recovered.