Not all skin cancers can't be burnt off with nitrogen (cryosurgery).
I just thought of something. There were troubles as well with the strong antibacterial/antiseptic prescription ointments doctors gave the clients as a temporary measure for skin cancers before surgery. The cancer areas, as well as the surrounding skin tissue, was already irritated, fragile and highly sensitive so some of those were just too strong and clients refused to use them after a few days or a week. They had terrible swelling, rashes and reactions from them, even if they were effective on the skin cancer. A person has to live in the meantime and quality of life is important.
The liquid antiseptics just burned and weren't effective at all. No cream of any kind could be used on or even near the cancerous areas. It made going out difficult.
We found that the EDP iodine powder was just right as a temporary, holding measure, it did not make the skin react and relieved the discomfort. I'm not sure you can get it in the US, but the powder form kept the area dry which helped a lot and it was antiseptic enough to help retard the cancer growth. Any mild, trustworthy OTC antiseptic powder from the chemist/pharmacy would probably work, but they need to be applied fairly often. Of course, we always covered the cancerous areas as well - even air could be irritating.
Hope that helps.