Lefthand coin was from a lot of mixed Italian States coins. I had almost given up on IDing it, but there's just enough of a circular wreath on the reverse to get a hint at what it was. 5.67 g, 23 mm. Doing a targeted search, there are only a couple candidates from Italy of that size with a wreath. So I think it's a Sardinia, 1826, copper, 3 centesimi. I'm not claiming to be able to read the date--it's a single-year type. To my delight, this is a coin I already have an example of, so I took a photo of the two side by side. Now that I know where to look, I can just make out the AR of "SAR" and maybe P of "CYP" on the reverse of the left one. Of course, it's not a valuable coin in such corroded condition. Still, it's cool to see that with any of the text or a hint of the design plus a size and weight, it's often possible to get an ID in even the least promising cases.
