Abstract: The invention relates to a cleaning fluid for a refrigeration plant, characterized in that it comprises a cleaning oil mixed with a liquefied carrier gas with which it forms, by expansion, a cleaning foam, for example the oil is a POE or a PAG and the gas is R134a. The invention also relates to a cleaning method. This comprises the following steps: the step of creating a foam from the oil and a liquefied gas in which it is at least partly miscible; the step of making the foam circulate in the said component; and the step of extracting the foam. In particular, the plant is rinsed with the gas separated from the cleaning foam, in order to remove the oil residues.