Yeah i still use paper bags for my garbage. More then a few times i wish i didn't. But i have a good (plastic) reason
Mixing bleach and ammonia can make lots of different things. You get one mix if it's cold, one mix if it's hot, one mix if you add some protein, one mix if you add some acid, and so on, and so on. But every mix includes things that can kill you in a very nasty way if you inhale them. Some of them can also explode.
As a general rule - yes. But as I said before you'd have to leave a coin in it for quite while for the vinegar to do any harm. And I'm not talking minutes here, it would probably take days. The true point is - there are better things to use, things that will not, cannot, harm the coin.