RE: Vinegar
Can't say about long term; I've only done it for a few cycles.
I will say that some of the brass acquires a slight pinkish hue around the neck, but I have seen that on old once fired brass, so I don't know if the vinegar turned it pink, or if it just revealed the pink under the gunk that my walnut media could not remove.
I forgot to mention that I add course sea salt to the vinegar to give it a little bit of mechanical abrasiveness.
I recycle the vinegar (try to keep it away from the salad dressing) and after a few uses, call it 300 pcs, it acquires a weak green tint, which tells me its leeching a little copper out of the brass. Considering how many copper atoms it would take compared to 300 pcs of brass, I have no concern. I think the work of sizing it is more detrimental by several orders of magnitude.
BTW - If someone has something more than anedotal evidence that I am shooting myself in the foot by doing this, I'd be interested in hearing it.