How to prep for grading?
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6 posts in this topic

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Is there a type of cloth that can be used to clear the surface of a coin before sending in for grading? Maybe compressed air? I recently received a damage grade on a coin that was freshly cut from a proof set (1964) due to me wiping it of with a microfiber rag. It seems crazy to call a visibly perfect coin environmentally damaged due to being wiped off but I don't yet understand the system of coin grading. Also, is "dipping" off limits? I see decent grades on coins that may or may not have been "dipped" years ago. Just trying to understand everything. Any help is appreciated. Thanks!

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Don't do anything to *spoon* with it before grading. Put it in whatever sort of holder they advocate, and send it in without harming your own outcome any more than the coin's history already has.

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11 hours ago, BrianP67 said:

I don't yet understand the system of coin grading.

I didn't at first either. I waited until I did understand it before sending any coins in.

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13 hours ago, BrianP67 said:

Is there a type of cloth that can be used to clear the surface of a coin before sending in for grading?

NO.

13 hours ago, BrianP67 said:

It seems crazy to call a visibly perfect coin environmentally damaged due to being wiped off

You didn't tell them you wiped it off, but they were still able to tell by looking at the coin.  Apparently they saw the fine hailine scratches left by the wiping and properly indicated as such.

13 hours ago, BrianP67 said:

Also, is "dipping" off limits?

I would not recommend using a commercial coin dip.  If you do anything it would be a soak and then flowing rinse with pure acetone.  Don't rub, don't wipe, don't even try to dry it off.  The acetone will evaporate off the coin in just a few seconds so don't try to hurry it up.

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On 10/3/2019 at 9:24 AM, Conder101 said:

...If you do anything it would be a soak and then flowing rinse with pure acetone.  Don't rub, don't wipe, don't even try to dry it off.  The acetone will evaporate off the coin in just a few seconds so don't try to hurry it up.

Acetone always leaves an ugly residue, regardless of purity.

Such acetone residue can not be conventionally removed from a coin surface by distilled water or by isopropanol because these solvents bead, while acetone covers the coin surface completely.

For example, an acetone dip may be used in conjunction with other solvents to provide a substrate free from residue.

One would need a ventilator hood, a probe sonication device, a temperature controlled nitrogen evaporator, supply of glass beakers, metal clips to fasten the substrate, etc

Don't know if a coin could be mounted in such a way as to survive the probe sonication which provides up to 1,000 times the power of tub style ultrasound.

See technicians exchange below:

Such a procedure is outlined in the response below: 

These are examples of coins having acetone residue:

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5CE185E3-25F7-4352-ACD6-201749EE1782.thumb.jpeg.a5d2254b77476d9ffa6ee948bc4e29bb.jpeg

Best regards,

Edited by Miguel del Rio
added another example

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A CoinTalk member asks, "Could it be residue from whatever organic was dissolved and then redeposited if the acetone evaporated without being thoroughly rinsed?"

This is true.

Acetone is such a good organic solvent that pure acetone is only theoretically available in the lab where it's distilled.

It takes additional solvents to remove acetone impurities using a probe sonicator.

Tub style ultrasound is not sufficient since the only solvent that may be used in the tub is distilled water. Use of other solvents present a fire hazard. Also, differences in acoustics could burnout the acoustic generator.

Differences in surface tension among solvents make sonication necessary near the target surface.

"Acetone HPLC Grade" has the least residue at 5 ppm.

Thank you for asking.

 
 
Edited by Miguel del Rio
spelling

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