For the last several years, I have been running DCS (Proto 3.0) and Legacy on Lionel Fastrack which has not been cleaned at all. I also run a standard gauge Proto 2.0 400E on tinplate tubular track which has not been cleaned for over five-years.
I have absolutely no problems with either Legacy or DCS and no arcing or sparking.
Fluids like alcohol contain up to 30% water and are hygroscopic (absorb moisture) and other harsh cleaners do more harm than good.
NO rust, EXCELLENT conductivity, and GOOD running! Works for me!