Ouch, that was too harsh. 🙁
Personally I don't think the coin needed cleaning. The coins details were already visible and it had a nice patina. I don't see how cleaning would add anything to the coin but if you insist I'd put it in olive oil for a week or two and just dry it with a soft paper towel. Anything harsher than that risks removing some of the coins patina or surface like what happened to yours.
The coin is most likely a RIC 60 variant. There are a couple of different examples on WildWinds, try matching yours to one of them.
As for keeping it it's entirely up to you. Depends on your collecting goals and how it fits into your collection. Do you need a Nerva as? Obverse legend is readable so the emperor can be identified, it's in decent shape with no significant damage and it's an authentic coin. I collect the Siscia mint so I don't need it. If I needed a Nerva as I'd keep it, at least until I found an upgrade.
I collect and deal in ancient Roman coin. In case you're looking for affordable ancient coins or need any help with the coins you already have send me a message.