I really don't recommend using vinegar for the stem. I was using it on mine for a while and regret it. I got some horrible smells in the stem. I had to soak it for like 4 hours in hot water and scrub the day lights out of it to get the smell out.
You can't go wrong with lemon juice. It's pretty cheap at the store and it lasts a long time. That stuff pretty much saved my stem