I guess the best thing is that you weren't using a Nihonto for your "test cutting."
The basic idea behind sword polishing is to keep the surface as pristine as possible - in your case, as good as it was when you got it - while removing as LITTLE of the metal as possible. Assuming your sword isn't stainless steel, it has a hard outer layer for cutting with a much softer inner layer for flexibility. The outer layer thus protects the soft inside metal, & should be maintained in the best shape.
Using solvents like alcohol won't cause erosion problems because there is no abrasive involved - just be sure to re-oil the blade when it has evaporated. But using any abrasive-based polishing material, which includes silver polish, starts the process of metal removal. You should also note that cutting most plants also causes wear & abrasion, as they usually contain silicon.
So feel free to use any polish that you prefer, Yorukage, but just be aware of what you're doing long-term.
Ken Goldstein
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Judo Kodansha/MJER Iaido Kodansha/Jodo Oku-iri
Fencing Master/NRA Instructor
"A positive attitude may not solve all your problems, but it'll annoy enough people to be worth the effort."