Noise reduction is a key challenge in solid-state nanopore experiments, as it directly limits signal resolution and the detectability of translocation events. Low-frequency noise, mainly caused by surface contamination and charge fluctuations, hampers event recognition, while high-frequency noise, arising from membrane capacitance, constraints the extraction of structural information. In this study, we systematically compared two established cleaning methods, oxygen plasma, and piranha solution, with multi-wavelength irradiation, to assess their impact on the noise characteristics of silicon nitride nanopores. The multi-wavelength irradiation was carried out using a newly developed commercial device specifically designed for cleaning membranes and TEM grids. All methods were applied under literature-reported conditions and evaluated through current-time traces, root mean square current (IRMS) analysis, and noise power density spectra. Oxygen plasma cleaning and piranha solution treatment resulted in a moderate overall noise reduction but were slightly outperformed by multi-wavelength irradiation achieved. These findings highlight that optimized cleaning and posttreatment protocols can markedly improve signal quality in solid-state nanopore measurements and suggest that multi-wavelength irradiation has an untapped potential for this purpose.