Best way to clean old tin

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Pic of tin

Best way is using oxalic acid in hot water (if it was a red paint design, hot water will fade it). You can buy oxalic at hardware stores - it's used to clean decks etc - or from Amazon. For one can you won't need much, just enough to submerge it fully. if you used a quart container, probably a couple of heaping tablespoons (meauring spoon, not regular spoon) will be enough. Mix it OUTSIDE or in a garage etc with door open, the fumes that are emitted during mixing aren't good for you, and of course soak it where a kid or animal can't get into it. After an hour or two you can pull it out using rubber gloves and wet a small rag in the acid solution to rub at spots to help clean - start slow - or use an old toothbrush. You can soak all day but keep an eye on it. A resoak in weaker solution may clean it more. When you take it out for good: rinse well with plain water, then submerge it in water with baking soda added to neutralize any acid that might still be on there. Pat dry as you can with a dry rag, put in front of fan, and then put a little oil on immediately (I use WD40) or light rust will come back. My beer can collecting buddies and I do this all the time, can make an incredible difference!

Yes! Like Iggyks above said - Oxalic Acid a.k.a. "Wood Bleach". It's not a miracle cure but it can remove much of that rust if used correctly. We used to use it on our "dumper" beer cans back around 1979-80 during the beer can craze.