Silicone cloths are fine for nickel. Just google 'nickel and silicone cloths' and see what many gun owners say. I'm used them on nickeled guns for at least 40 years with zero issues. Now what can happen to the typical gun owner with several guns is that the cloth gets contaminated with other solvents and cleaners and that potentially causes problems. Also, there are gun cloths that are specifically for removing lead...don't use those either. They'll damage both nickel and bluing. But in your daughter's case most of this is probably a non-issue for now. And yes, Walmart and Academy have silicone cloths. And yes, Prolix is also very good stuff. Not any better than CLP for cleaning the bore, IMO, and harder to find, but it works fine too.