Purpose To compare the effect of solutions of effervescent tablets (ET), cetylpyridinium chloride (CPC), and experimental solutions of Ricinus communis on the surface of cobalt‐chromium (Co‐Cr) alloys. Materials and Methods Fifty‐five specimens of Co‐Cr were prepared by the lost‐wax casting method using circular patterns (∅12 × 3 mm). The specimens were randomly divided into 5 groups: deionized water (control); 2% R. communis; 10% R. communis; ET, and CPC. The surface roughness of specimens (n = 10) was evaluated before immersion (baseline), and at simulated times of ½, 1, 2, 3, 4, and 5 years, by laser confocal microscope (Sa, μm) and profilometer (Ra, μm). The surface topography and chemical composition (n = 1) was qualitatively analyzed with scanning electron microscopy (SEM), and energy dispersive X‐ray spectrometry (EDS). Data were subjected to Kruskal–Wallis followed by Dunn tests, and Friedman followed by Wilcoxon tests (α = 0.05). Results For Sa, there was no difference for the solution factor. For the time factor a significant difference was found with 2% R. communis solution among baseline and ½, 2, 3, and 5 years (p < 0.001) and with 10% R. communis solution between 1 and 2 years (p = 0.007), with decreasing roughness over time. For Ra, cetylpyridinium chloride exhibited less roughness than 10% R. communis solution in ½ (p = 0.048) and 5 years (p = 0.013). In the SEM and EDS analysis the solutions did not present deleterious effects or changes in the chemical composition on the surfaces. Conclusions Although a significant difference was found for the roughness, the results, below 0.2 μm, are clinically acceptable. Thus, all solutions can be used safely in removable partial denture cleaning for a period of 5 years.