[X] Illegitimate means. You're not really familiar with criminal stuff, but there's probably a… black market, or a fence, or whatever in town. You bet Doukas would know. A fence would probably be less well-equipped to identify specific magical functions, but would probably also ask fewer questions.
[X] Shops. It looks like there are some shops in town you might be able to sell to. One of them even looks like it specializes in minor magical tchotchkes. Any such shopkeeper worth their salt should be able to help you identify the enchantments on the minor magical trinkets you have. Hopefully they take pre-owned, slightly bloody jewelry. Maybe you should wash it off first?