Environmental pollution in large cities primarily originates from the transportation sector, whether private or public, which relies heavily on fossil fuels. The three-way catalytic converter is a technology that considerably reduces polluting emissions such as carbon monoxide, CO, nitrogen oxides, NOx, and unburned hydrocarbons, HC. This study focuses on comparing three commercial cleaner additives to increase the useful life of a sectioned commercial catalytic converter under real idle and acceleration conditions at 2500 rpm. The composition of the gases emitted after the application of the additives was analyzed, revealing that the reduction in polluting gases is achieved by using additive 3, which is primarily composed of normal hydrocarbons and iso-alkanes (C10–C13), cyclic hydrocarbons, 2-ethylhexan-1-ol, and benzyl alcohol. The semi-quantitative composition of the monolith was analyzed in three sections by scanning electron microscopy SEM–EDS. The results showed that the composition is inhomogeneous, with various compositions of Mg, Al, Si, Zn, Ce, and Zr, as well as traces of La and Pr.