Varnish that forms on metal surfaces due to oil degradation is detrimental mechanical components’ functionality. In this project, we used a custom testing rig to evaluate the varnish removal capabilities of chemical cleaners under varying conditions. Building on previous improvements to a testing rig, we tested chemical cleaners on artificially varnished metal coupons and heat exchanger plates with real varnish to compare the effectiveness of different chemical cleaners. Also, we studied the varnish pieces trapped in filters during testing using image processing to measure their areas and quantify the number of pieces in a filter. Additionally, elastomeric seals used during testing were subjected to tensile tests to determine their mechanical properties after exposure to chemical cleaners and operational conditions. The results of these tests and analyses contribute to study the performance of chemical cleaners, measure and quantify varnish pieces removed, and examine elastomeric seals’ deterioration after exposure to chemical cleaners.