Featured Thoughts on Renwax?

Jump in and buy a few...there is nothing like holding a 2000 year old piece of history in your hand.

 

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The main thing to remember about cleaning modern (after 1500 or so) coins is that you don't want to rub the surface in general. Rubbing can cause scratches and the newer the coin is, the more detrimental to it's value it is. That being said, using harsh chemicals (acids and bases) on the coins can also affect the surface. What we are left with is soaking. Water, acetone, alcohol and xylene are all used in some cases. Other than this, seek out help for specific cases.

 

If ( and I realize it doesn't apply to most ancient collectors ) one is going to send to a TPG and they are ones that use "Sniffers", they will probably set off alarms as it is similar to putty and other filler materials use to "doctor" /fix modern coinage ( and probably some ancients also).

 

Ipana

 

?

 

Excellent point. Since cleaning (even what would qualify for "harsh cleaning") is acceptable in ancients and perhaps renwax is acceptable in ancients, would the TPGs disqualify a coin for such...@Insider any insight?

 

Why would a TPG "sniff" for evidence of cleaning when it is known and accepted that virtually all ancient coins are cleaned?

 

I don't know if they do, but it can be done rapidly and inexpensively. I realize ancient coins are cleaned, but is it acceptable to fill cracks or damage with putty or wax or to find such after purchase and breaking out of a slab as many profess to do?

 

Everyone is so good on here and understanding - I hope a couple more newbie questions from me won't push anyone over the edge..lol.

-What is TPG ?.. is this a term for the various paid services that validate/slab coins?
-"Sniff" - is this a method they use to determine whether a coin is legit, fake or "enhanced" ?

..part of my original post was asking if using Renwax was acceptable to ancient coin buyers .. especially if not noted in the coin description.. I personally have no issue with it. BUT I only deal with very low end coins. I assume when the monetary risks are higher things get more interesting...

Would really appreciate any possible clarification..

Cheers!

 

Yes, a TPG is a third party Grading company like PCGS or NGC, etc. A sniffer is sometimes called a Puffer, but it is a type of mass spectrometry which detects chemicals in the air or wipe sample based on its programmed intent. Some have a database for explosives, drugs, etc. for airports and other entry points, and some are programmed for environmental factors. I do not believe the TPGs have said exactly what theirs are programed for for, but materials such as putty, epoxy, waxes, chemicals probably are unless they are similar to verdi-care (tm) which are so thin and attracted to a coins surface, that they do not seem to be ( personal experience). IMO.
Jim

 

Great information - Thank you!

 

Anyone use renwax on silver or is it primarily used on bronze?

 

Yeah, they use a devise to detect the olfactory signal emitted by certain chemicals. I have found a way around this is to use bacon grease (ah...bacon). They have never rejected a coin for smelling like bacon!

 

I am thinking a bacon smell would increase value.

 

What a wonderful idea!!

I just finished my breakfast and left a lot of bacon grease on the frying pan, oh, I mean, bacon coin wax on the frying pan.

 

I love and respect you, but you are waaaaaaaaaaaaay off base on this one. The "sniffing" has nothing to do with sampling vapors or with mass spectrometry. The two methods used (as far as I know) are infrared analysis and x-ray spectrometry. These techniques detect organic and inorganic substances on the surface. The reason VerdiCare passes is that the techniques (infrared for this) are just not sensitive enough to pick up such a thin film. Gas sampling mass spectrometry is much more expensive and wouldn't have that much use. Perhaps @BadThad would comment here since VerdiCare is his baby.

 

Well if that is now so, I am glad to change my answer. The latest I can find on it is 2014 PCGS show and Tell video, and the XRS was mentioned as a $50,000 "ray gun". I didn't mean to imply I knew exactly what they were using currently. Jim

 

Who knows, they might change, but mass spectroscopy is really heavy duty stuff.

 

The "Ray guns" are selling on ebay for avg. of about $20,000 now a few 'repurposed' ray guns have shown up in military surplus for much less, but they go fast by jewelry and bullion dealers, on about 1-2 days.

 

As I recall they use FTIR ATR - which is not a very sensitive technique. That's why they picked grease in the PCGS video, they slather on a TON to a coin and say "see how it's detected". Not hard to detect if there's a 2+mm layer! If they would have picked Verdi-Gone in that video, they would have not received ANY signal at all as that product had almost no IR detectable materials in it. I was LMAO that it was even in their library.....most likely nothing but unmatchable signal noise.

Very thin layers cannot be detected with reflectance photospectroscopy - there's just not enough signal getting back to the detector to differentiate from the noise produced. It's hugely different from normal FTIR where the incident light passes through the sample.

For sure they're not using MS! The people running the Sniffer are not chemists - just regular PCGS employees trained on running the instrument. Running a mass spec is pretty serious business - even for an analytical chemist. Many chemists that run MS are dedicated to doing only that. The equipment and people that run it are very expensive!