Glad you asked. I just found this tidbit from the original blurb for Xtreme AV’s Quicksilver Gold contact enhancer that was introduced about 12 years ago. In addition, there are at least a few technical papers from IEEE etc. addressing arcing and micro arcing in electrical contacts. Ditto the dissimilar metals issue I mentioned.
“Machined and/or plated electrical contacts, when viewed under a microscope, actually have a rough surface finish allowing less than 5% of the contact’s surface to actually make contact and transfer vital energy to your electronic components be it AC Power, Audio or Video signals. In addition, these rough contacts cause micro-arcing to take place generating noise which is then transferred and amplified in your system along with the complex, multi-frequency Audio and Video signals resulting in a dramatic loss in resolution, low-level information retrieval and a less natural 2-dimensional presentation. It does not have to be this way!”
Also, this is from Mapleshade’s website regarding their Silclear contact enhancer, circa 20 years ago,
“Technically, the SilClear engineering objective is simple: to create the thinnest possible continuous layer of silver between the two mating surfaces of any electrical connection. The test results are unequivocal: SilClear improves sound. The reasons are not so obvious. We hypothesize two mechanisms. One is the beneficial effect of a near-monomolecular layer of silver in reducing skin effect (i.e., the velocity disparity between signal propagation on the surface and in the interior of a conductor). Second is eliminating the distorting diode effects (i.e., unequal resistance to the + and - halves of a music waveform) of the inevitable oxide films on any conductor surface.”