Ethical Or Not?

I feel that a treatment of olive oil or acetone are not 'cleaning' agents. They are enhancers. If there are impurities in either then damage can be done to the coins so proceed with caution.

Nothing unethical about it. Are you sure they dip in in olive oil and not something else, such as acetone?

If you use olive oil, better get it completely off the coin with acetone and then rinse with distilled water and make sure the coin is completely dry. The olive oil would most likely have a long term effect on the surface of the coin and the acetone will probably react with the holder and reflect the reaction on the surface of the coin. Any moisture on the coin from the water will cause corrosion.

I thought you werent supposed to clean coins ever....thats just what I have read,but I do like the looks of your nice brown cent.

In my most humble opinion; you have the right mindset. However
conserving a coin is not "a cleaning" but some does occur. I conserve coins (mostly LWC) constantly because of the Verdigris found on most circulated cents. I also put the term "Conserved" on the holder. That's the part that many collectors forget and exposes them to being labeled un-ethical. If you want your collection to last and not have a green moldy look to them, you should treat the coin to stop the spread of the problem.

If the coin is one of great value, I wouldn't touch the coin but I would send it to NCS for grading and encapsulation. If the coin is conserved by NCS, NGS will encapsulate the coin with details concerning the damage or conservation.

As far as most TPGs are concerned, they can tell the difference and
It's a slippery slope either way you go, just don't pull out the "Brasso" and a brush to make it more shiny. Once you give a coin a harsh cleaning, it's worth is reduced to its melt value. A well conserved coin will always retain some value, especially to its owner.

seal006,
Yes, most coindealers do enhance the look of their coins for sale. But most use the "safer" ways described. There are many many tricks to enhancing the look of a coin, depending upon the type of metal. Copper and Nickel are difficult to alter without effecting the patina or luster of the coin. Too much luster with some wear, in silver coins can be an indicator...pinkish tone in copper...ect.

carmkle..I would have to disagree with one point you made re: TPG's telling the difference. I have seen NGC and PCGS grade many silver coins that have been dipped come back with MS certifications. It happens.

just steer away from that 1899 Morgan that looks like a belt buckle, smooth surface, passing off as MS.

unethical?...to me if the surface (not dirt, muck, ect.) is altered, yes.

Also, many dealers and collectors alike dip silver MS coins with E-Zest or another solvent designed for cleaning silver coins. The coins if dipped right will retain the luster and original look, so there are many coins on the market that have been dipped, and TPG's generally consider those coins market acceptable, and they slab them without a Details grade. Some think dipping a coin is a substance other than acetone is unethical, some do not.

I have a whole section devoted to olive oil in my book. I do not recommend it for coins at all, especially as a long-term surface treatment. It contains a LOT of different acids which will act to damage the surface with time.

From my experience, most dealers that have nice coins is because they selected them like that. They cull the junk and keep/sell the best. Some may use mineral oil products like Coin Care, but it's not that prevalent. It happens, but most dealers realize their customers will spot it.

I can spot an oiled coin in hand pretty quick. Also, the surface will feel slick and the surface debris has a "moistened" look.