I'll be darned... I came back to this thread to see if there was anything new and found this Collidal Silver and H2O2 (Hydrogen-Peroxid) post. I find this very interesting, especially after you mentioned using CS on things like burns. I experienced a cast iron branding and tried your recommendation, and it worked. Not only calmed the pain down considerably and quickly as you said, but healing was fast as well.
So, started using CS for other scrapes (chainsaw + wood cutting = trees falling and getting scraped up with the branches) and it has worked.
But CS soaking to eradicate age spots, am going to have to give this a go. I make my own CS so this is feasible.