I use the DS Audio, stylast frequently, and every now and then AT liquid / brush. I never had much luck w magic eraser or blue tac…
Having said that with 30+ years experience in tech, there is no way i would publish that photo without some form of comparison to a control ( see design of experiments, ishikawa diagram, etc… ) if as asserted by Wally that the residue presents in 8 hours, it’s just not that difficult to build a slam duck root cause case…..or not…..