A method for cleaning a petroleum plant arranged to process crude oil or equipment of the petroleum plant during a running of the petroleum plant, comprising: maintaining, during a treatment period, the petroleum plant under a production operating condition, typical of the plant itself, which includes providing fresh feed to the petroleum plant; while maintaining the petroleum plant under the production operating condition, there is carried out both of a) and b); a) introducing in the petroleum plant, during the treatment period, first and second hydrocarbon-based treatment fluids self-produced; b)varying an established feed rate, present at initiation of the cleaning of the petroleum plant or equipment of the petroleum plant, which established feed rate ranges from a maximum operation rate for the petroleum plant, which is inclusive of a design rate for the petroleum plant, to a minimum operation rate which is set at a level for satisfying a minimum production operating state in the petroleum plant; wherein said introduction of said first and second hydrocarbon-based treatment fluids and said variation of the treatment feed rate generates an additional source for distallation with respect to the amount provided by the established rate; and distilling said additonal source for distillation for the purpose of self producing said first and second hydrocarbon-based treatment fluids for plant cleaning and re-circulate at least a portion of said first and second self-produced hydrocarbon-based treatment fluids inside the same petroleum plant or equipment to create a closed or semi-closed loop during plant run, whereas another portion of the distillates makes up the petroleum plant production and/or the normal distillate flow stream, to achieve a distillation yield increase and the reduction of coke formation on catalysts and the removal of coke on catalysts. maintaining, during a treatment period, the petroleum plant under a production operating condition, typical of the plant itself, which includes providing fresh feed to the petroleum plant; while maintaining the petroleum plant under the production operating condition, there is carried out both of a) and b); a) introducing in the petroleum plant, during the treatment period, first and second hydrocarbon-based treatment fluids self-produced; b)varying an established feed rate, present at initiation of the cleaning of the petroleum plant or equipment of the petroleum plant, which established feed rate ranges from a maximum operation rate for the petroleum plant, which is inclusive of a design rate for the petroleum plant, to a minimum operation rate which is set at a level for satisfying a minimum production operating state in the petroleum plant; a) introducing in the petroleum plant, during the treatment period, first and second hydrocarbon-based treatment fluids self-produced; b)varying an established feed rate, present at initiation of the cleaning of the petroleum plant or equipment of the petroleum plant, which established feed rate ranges from a maximum operation rate for the petroleum plant, which is inclusive of a design rate for the petroleum plant, to a minimum operation rate which is set at a level for satisfying a minimum production operating state in the petroleum plant; wherein said introduction of said first and second hydrocarbon-based treatment fluids and said variation of the treatment feed rate generates an additional source for distallation with respect to the amount provided by the established rate; and distilling said additonal source for distillation for the purpose of self producing said first and second hydrocarbon-based treatment fluids for plant cleaning and re-circulate at least a portion of said first and second self-produced hydrocarbon-based treatment fluids inside the same petroleum plant or equipment to create a closed or semi-closed loop during plant run, whereas another portion of the distillates makes up the petroleum plant production and/or the normal distillate flow stream, to achieve a distillation yield increase and the reduction of coke formation on catalysts and the removal of coke on catalysts.