How Cleaning Affects Value And Eye Appeal

Why not post a few pics? Depending on the extent of the ED, you may have some luck improving the aesthetics with acetone or xylene as hfjacinto said, though it will likely stay a problem coin. If those two solvents don't work, I'm in the "leave it be" group. "Bright and shiny" doesn't add any value to a problematic coin, and will likely make it worse.

Be extra careful with xylene. It is not skin friendly.
John1

"Cleaning" is not a precise term in numismatics. A dip in acetone could be considered cleaning (that's OK), so could a scrub with abrasive bathroom cleaner (very bad). You really need to show us the item and tell us what you want to do to it. Professional coins grading companies can "conserve" coins, which in my mind is a safe way to clean coins and improve their appearance.

Let's post some before and after pictures of coin that I have treated.

Case 1: A Tasmanian copper tradesman token I experimented with to try to remove bright green "bronze disease" corrosion.
Before (from its appearance it seems a previous owner attempted but ultimately failed to remove the bronze disease):


After (numerous cleaning attempts which did nothing, finally with concentrated ammonia):


Now, which of these coins would you rather have? Personally, I think it's subjective. The green is ugly, but so is the orange pitting. The coin has since retoned to a more appeasing brown, but of course the moon-crater pitting remains.

In terms of resale value, has my cleaning made things better, or worse? I don't think there's actually much difference - I wouldn't say I have improved it to the point where I've increased its value.

Now let's look at case 2. This one is a debased-silver coin (50% silver), so it stood a better chance at surviving a harsh cleaning.

Before (it appears to be a metal detecting find):


After (1 week soak in EDTA solution):


Now, I don't think anyone can argue against that this coin has undergone a positive transformation, from "are you sure that's a coin, it looks like a rock" to "yeah, it's got a couple of issues on the obverse, but it's still in pretty good condition". This treatment has certainly "added value".

Finally, the other thing to consider when "Adding value" is the cost of the treatment itself. Cleaning chemicals aren't free, and your time isn't free either. You'd want to be reasonably sure of recouping the cost not only of the original corroded coin, but of the time and chemicals you've put in into trying to improve it.

Conclusion: do it for scientific curiosity, or do it in the spirit of trying to "rescue" a coin that would otherwise be condemned for scrap metal. But don't do it for profit; it's a gamble on whether or not you will actually recoup your money.

Nice job on the florin!

Same applies with ancient coins that have been recovered from burial. It is always going to be a gamble, but in most cases, the professional museum curators that clean them,
have learned that in most cases, the gamble will pay off.
Professional experience in this sort of cleaning and preservation is essential.

Cleaning and preservation of detector finds of modern coins is a good place to gain that experience.

Does EDTA damage the original surface of a coin compared to acid "dips"?

Thankyou.