Hey Banjo Boy
Jez is so right when he says avoid water and washing up liquid. About 15 years ago I came home with my first box of dirty tins. I filled the sink with warm, soapy water and unceremoniously dumped them all in. I left them to soak for an hour and came back to a sink of paint and tin. Unfortunately the paint wasn't on the tins anymore. Even brief exposure to soap and water can be disasterous. Jez is also right about getting even plain water on them so I avoid the sink at all costs except to sometimes gently Brillo the unpainted lids of some of them.
What I do use to clean my tins has met with gasps of disbelief from some collectors but it works for me. I can count on one hand the tins I have damaged with my methods and I have cleaned hundreds of tins.
Light Soil- I use something called a cleaner/wax that is meant for car finishes. It has very fine abrasives and wax together so I kill two birds with one stone.
Medium Soil- Again I use a product for cars. It is meant for cleaning aluminum rims. Yes, it has ammonia and bigger grit but as long as you don't rub too hard or leave it to sit you can obtain some spectacular results. I follow this up with an auto wax to bring out a shine and protect the paint. There are also U.V. protectors in some auto products so they are protected from the fading properties of sunlight.
Heavy Soil, Rusty Spots, Old Labels- I know this may seem crazy and I don't know why it doesn't just melt the paint away but I use a product called "Peek" that is meant for cleaning silverware and other metals. You can actually smell the ammonia in it but I have used it effectively on tins that were a lost cause. It has also worked well on removing old gummed labels. A lot of North American tobacco tins had quite large tax stamps affixed up the side and over the lid. If I carefully apply small amounts to the label and rub it in the cleaner seems to melt the paper and gum away before damaging the tin. Again I follow this up with a wax finish.
The bottom line is to experiment with a variety of products. Different name brands of the same product will render different results so try it on a tin that is a lost cause and you can afford to destroy. I use clean white cotton rags that I cut up from my old t-shirts and always keep checking the rag for signs of paint transfer. Another thing is to learn what tins can be saved and what ones should be passed over when buying.
I was involved in a similar discussion on the old site where I listed much the same advice and was left thinking WTF when some members chose to dispute my methods. They work for me. End of story.
I have gone a little nuts posting in the last few days but I had a couple of days off work and decided to get the camera out and immerse myself in a little digital madness. This is the last photo I have for now and even though it is not a tin it does involve the subject of fertilizers and manure.
A couple of AA members should recognize this piece from 1894.
