I've been using Joy dish soap, probably as good as any, and a nylon bristle brush to soap my pans. A friend told me they thought the nylon might be abrasive enough to scratch the tin.
She uses a wash cloth to do her copper/tin. I've been using a nylon bristle brush for years, and so far so good. OTOH, I haven't been using copper lined tin for years, and I don't want to expose any copper.She recommended a Tampico bristle brush, but I haven't found one locally.
I know from ebay seller Harestew to avoid Barkeeper's, or any scrubbing product. So what is your copper/tin cleaning method ? Clarification, I'm not referring to bringing darkened tin back to shiny brilliance. I'm fine with dark tin through cooking. Just talking about cleaning the food residue.