1909-S VDB

With that, I'd state the coin has no financial value. It's an heirloom with sentimental value and you want it to survive for your grandson.

If you were leaving him a Mustang, would you pass on a rusty carcass, or try to fix it up? If it's fixed up, are you going to keep it in the garage or show it off by driving it around. Your grandson would not want it if he thought he had to keep it locked up in a hermetically sealed garage.

TPGs have created this atmosphere that it is taboo to "clean" coins.
Well, that's fine for those in the business of selling proof coins or preventing cheats trying to get an extra buck. But,you'll find that well over 80% of all coins on the market have been cleaned. Another 5% have been "conserved" and another 5% are in sealed packages from the mint. Doesn't leave too many unadulterated coins. And, many of those cleaned/conserved coins are in TPG holders. (Look it up.)

You've got an heirloom, not a museum piece. But, even museums conserve their coins.

I'd consider as a minimum, a dip in Acetone (not fingernail polish) to loosen the grease followed by a cheap toothpick to gently push the dirt/grease off the coin. (Cheap toothpicks are usually a softer wood.) Soft tooth brushes work well, but not all agree with Acetone and the idea is to get plastic off the coin.

Dip the tip of the toothpick in the Acetone and rub it on a piece of glass to turn it into a soft brush. Gently push the toothpick into the dirt/grease. Usually, it will pop off in chunks. (I do this under a microscope, so they look like chunks.)

If the coin is AU, or better, a toothpick or cotton swab can harm the luster. I would advise not to clean these mechanically.

Dip coin again in the Acetone to remove the debris. Wipe (don't scrub) coin with cotton swab soaked in Acetone to remove residual grease. Air dry the coin (takes seconds.) Then, dip in distilled water and pat dry with a dry cotton swab.

Liquid Acetone has NO chemical reaction with copper. Acetone, air and copper do, but any Acetone left on the coin will completely evaporate and the duration is not long enough to cause a reaction. If you don't use distilled water, you will leave some minerals on the coin (think dishwasher spotting on glass.)

Wear a nitrile glove on the hand that handles the coin. (Again, don't want the glove to dissove in the Acetone.) Then, when you put the coin back in it's display, it won't have a fingerprint that slowly eats at the coin.

PRACTICE on common coins first. It's amazing what you can do with a toothpick.

Again, if you are looking to sell this coin, don't change it. Somebody, some day will submit it for grading and the TPG will see hairline scratches (probably from a previous cleaning, or just slipping it in and out of the display you have) and then refuse to grade it. When you pass it on to your grandson, any hairline scratches will have developed a normal patina on them again.

Obviously, I'm very opinionated on the topic and to some, I've destroyed all my coins. But, my grandkids enjoy my coins, handle them, know some of their history, and bring me the coins they find to be "restored." I know they'll enjoy their collections.

You're correct in not trying to remove anything from the surface of your coin. As BadThad noted, removing the contaminants will expose long covered metal that will likely be a different color, possibly porous, and "vulnerable" to further problems.

Should be authenticated with PCGS being the TPG of choice these days.

Thank you for tempering my post with yours.

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"Never be induced to pay extravagant prices for worthless coins. There are some coins which command and are worth a large price. But these are, in fact, very few. Even the rarity of a coin is no test of its real value to a collector. It may increase the price of the article; but the young collector should bear in mind that the high price asked for a coin because it is rare, ought not to make him desirous of possessing it. The moment that the collector begins to value coins because of their rarity, he descends in the scale of Science; and when he seeks to possess rare coins merely because of their being rare, he becomes a speculator, envious and uncomfortable in the presence of others, and ceases to be a genuine Numismatist.

Read as you collect. Never let a coin lie in your cabinet that you cannot give the history of, or connect with some historical event if it be possible. Be careful that your collecting does not become a mere matter of curiosity. Let it rather be a constant aid to your study."

from The American Journal of Numismatics
April, 1872