Collectors get angry all right but they will complain either way.
Oh that coin has been dug......better knock a few grades off of it. Oh that coin has been cleaned......better knock a few grades off of it.
You will find conflicting opinions in the metal detecting community as well. Too many green globs posted and I scream at my computer "Clean that bloody thing already!"

Especially when they ask to identify it. Some will harp about patina. Sorry people, patina is important for ARTIFACTS, not modern coins. Collectors find green coins hideous unless they're really old.
If you're not selling then keep it how you like it, as it is YOURS to do what you want with it.
In my experience, a collector will pay more on a cleaned silver coin than one that is all black from tarnish.
Don't let anyone pull the "original toning is lost" crap on you either. Toning only applies to circulated coins that have NEVER hit the ground. Once it hits the ground, it's a whole other ball game.
Why would someone want to buy a coin that they can't see?
Cleaning should always be on the conservative side. It's better to under-clean a coin than to over-clean.
The rock tumbler idea is good for CLAD only!
Don't use lemon juice or vinegar on copper/brass coins. It will turn it a sickly looking orange and leave pitting.
I normally stay away from posts like this as it can cause arguments.
For the record, this is MY OPINION ONLY.
Cheers,
Dave.