What Happens If You Dip A Proof Coin?

Just carl has a point. It should be stipulated that the term "dipping" has a precise numismatic definition involving the use of a thiourea solution to acid-strip the surfaces of a coin. The fact that the term can be used with other connotations doesn't change what most experienced numismatists hear when the word "dip" is used. The "standard" dilution considered "full strength" is what you get straight from a container of E-Zest.

This stuff works well on silver and nickel, but in my experience () turns copper an ugly unmistakable orange. One may assume (although I've heard stories of outliers) that a maximum of ten total seconds in dip will kill a coin. It may be diluted in water, and the speed of the effect is diluted in nice linear fashion.

It's a subject which should never be discussed casually, as dangerous in its' way as acetone is in another.

Do not push the button.

Do NOT open the jewel lustre and step away from the dipping jar! . Any of us here have all tried dipping cleaning and various other methods of "conservation". Some are somewhat successful and some are disastrous. If the coin was a valuable early proof or mint state coin NEVER touch it, you can try NCS or a conservation service . For a cheap proof with hazy toning sure give it a go to see what happens. If you dip a US clad silver proof you can often tell it is a dipped coin as the edge copper colour will look off.

AcesKings' coin is an anomaly - thiourea cannot cause those lines on the coin. It might have been brushed and then artificially toned to hide the brushing. Seen that before.

Here's a relevant dipping story for you.

Years back, I snagged a 1921-D Morgan from ebay. I didn't save the auction images, but basically this is what I had to go on:





See the prominent die crack from the second star to the date? VAM-1F, one I really liked and had never owned in Mint State. Better yet, it sure looked to me like a candidate for a (careful) dip - seemed like the toning inhibited the grade. So, a potential Condition Census variety. I bought it with the intent of cracking, dipping and resubmitting. So, when I received the coin it immediately got cracked. It was duller in person, but I knew that to be an artifact of bright lighting. Under area lighting (a BR40 flood a few feet away), it was more like this:





I was able to duplicate the brighter images with more direct lighting, and the duller real-world finish actually encouraged me. I saw easy 64+ detail under the ugly color. Now, the darker toning at the rims is problematic - it's about the maximum toning thickness you can remove with thiourea without destroying the coin so I contemplated things carefully.

And dipped it. Here's what I got. Mind you, PCGS slabbed it.





It wasn't toned, it was smoked.

The haze is what I keyed in on. I assumed the scratches were a secondary issue anyway.

I have a number of proof nickles with that hazy, milky spotting and especially a kind of "rim" around the edges. I'd purchased a number of other proof nickles (building a set of proof Jeffs) from the dealer and he threw these in for face...didn't want them on his table! I'm going to try the "dip" method on these. After all, even as a compromised proof I'm into these for 5 cents...they won't lose any value!