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 Replies: 33 / Views: 3,170 |
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Pillar of the Community
Canada
1267 Posts |
Do you clean your coins?No! 
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Pillar of the Community
Belgium
2078 Posts |
There is no such thing as a plastic additive that will stay in the plastic I am a university specialist with 23 years of experience in the field of plastics and plasticizers pvc has a plasticiser heavily or lightly plasticised this plasticiser will migrate and come out of the plastic On plastics in general some plastics are accepted as foodcontactgrade that means under laboratory conditions the amount leaching out into margerine is below the legal microgram level allowed On a funny note at one time in my live I had to calculate the amount of dustrepellent antistatic that went into the dashboard of a car The chemical of course migrates out of the plastic at any temperature The chemical being more expensive then the dashboard plastic the calculating exercise was to make sure that dust only was attracted to the dashboard well AFTER the gurantuee on the car expired  Edited by ageka
12/03/2006 08:21 am
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Pillar of the Community
 Egypt
3470 Posts |
quote:
Originally posted by scoutjim99
try olive oil or ,even distilled water long soaks only air dry, are they really incrusted ?
one or two small and medium size black dirt spots in-between the words |
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Pillar of the Community
Egypt
3470 Posts |
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Pillar of the Community
Egypt
3470 Posts |
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Pillar of the Community
Egypt
3470 Posts |
quote:
Originally posted by crystalk64
If you have any sense of REAL value and history you NEVER EVER clean a coin. While they may pretty up a bit it is almost impossible to clean without damaging the coin. A real collector or dealer will ALWAYS check a coin with a magnifying glass before purchasing and cleaning WILL destroy the value, even in key dates, so if you have any desires in the future about your collection DON'T clean your coins. I have an example of value lying right in front of me at this time. My dealer bought an 1830 Bust Half Dime which should have run around the $35 to $45 level for practically nothing due to what he thought was glue on the reverse of the coin. He made NO attempt to clean this coin but did offer it to me for $4.00 and then only charged me $3.00 when I decided to add it to my son's collection. Upon returning home I decided to take the Half Dime out of the 2X2 to clean it with a little MS-70 which I would never do but seeing how this coin was already a problem I felt I had nothing to lose. As soon as I touched the reverse of the coin I realized it was NOT glue but the sticky remains of tape as someone had apparently scotch taped the coin to a page or piece of cardboard at some period in time. The sticky rolled right off after applying a drop of water and I managed to get the "buy of the week" that had been perceived by my dealer to be a ruined piece of junk. This is an example of why there are DO"s and DON'T's in our hobby that can and will destroy the value of your coins. In this particular case someone LOST the real value of his coin simply by scotch taping it. The dealer noticed the residue and the value dropped to nearly nothing! Cleaning coins, especially a harsh cleaning, destroys the value and regardless of the rarity MOST collectors will not purchase a cleaned coin. And most attempts at cleaning, regardless of how careful you are, will show under magnification. Do yourself a favor and accept coins as they are and avoid cleaning at all costs. If you don't like "dirty" coins then pass on them!
Old Dan I can't believe you send those precious little darlings down to the creek all by themselves. Here in the mid-west we always hire a body guard to send the kids off skinny dipping and if one is not available a good English Coin dog will keep them herded up and safe!
Of course, if there is copper in the bunch, we send along a good Kentucky Copper Hound as well!
Your example is very demonstrating, Thanks crystalk64  |
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Pillar of the Community
Egypt
3470 Posts |
quote:
Originally posted by Sap
quote:
Originally posted by just carl
Of course never clean a coin. Also, note people that tell you it is OK to clean off the PVC with Acetone are truly wouldabe chemist at heart. PVC is a stable, at normal temperatures, Plastic. It will not even begin to melt until 212 degrees C (413F). And if your coins have been in that amount of heat, I don't think it is the PVC you have to worry about.
Sure, pure PVC is a relatively harmless, stable plastic, though it does degrade over time. It's also hard and brittle, quite unsuitable for making coin pages out of. But PVC is cheap. That's why, when they made those nice soft flexible coin pages out of PVC, they pumped it full of plasticizers. If the plasticizer was not chosen carefully (ie they chose "cheap" rather than "acid-free"), acidic by-products would slowly leach out of the plastic onto the coin. It's this which causes most of the "PVC damage", the green stuff which is actually a sticky mixture of plasticizer, degraded and depolymerized plastic, water, and metallic compounds formed from the reaction between the coin and the acid - not that much different from old stickytape residue.
The main reasons that removing it is recommended are, as far as I can tell:
- it looks ugly, and is easily removed by solvents such as acetone without harming the coin further. Thie coin has, however, already been damaged, and the surface is usually left "hazed".
- the green goo can migrate back into whatever new plastic container it's placed into next, potentially starting a new cycle of plastic degradation and coin damage.
You may occasionally find 1970's-era PVC albums and pages where the plastic has gone hard and brittle - I suspect most of the plasticizer has escaped from these over the years, leaving pure PVC behind. These should, for the most part, be "safe" to store coins in, if a tad difficult to get them in and out.
As usual you are so informative and professional Thanks a lot Sap |
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Pillar of the Community
Egypt
3470 Posts |
quote:
Originally posted by ageka
There is no such thing as a plastic additive that will stay in the plastic
I am a university specialist with 23 years of experience in the field of plastics and plasticizers
pvc has a plasticiser heavily or lightly plasticised
this plasticiser will migrate and come out of the plastic
On plastics in general some plastics are accepted as foodcontactgrade that means under laboratory conditions the amount leaching out into margerine is below the legal microgram level allowed
On a funny note at one time in my live I had to calculate the amount
of dustrepellent antistatic that went into the dashboard of a car
The chemical of course migrates out of the plastic at any temperature
The chemical being more expensive then the dashboard plastic the calculating exercise was to make sure that dust only was attracted to the dashboard well AFTER the gurantuee on the car expired
Thanks ageka |
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Pillar of the Community
Egypt
3470 Posts |
quote:
Originally posted by scoutjim99
One of the excepted exceptions to the rule is Ancients . or at least one encrusted with earth and contamination after being buried for So many Years or In the Depths of an Ocean
Thanks Jim ( Shukran ) |
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Pillar of the Community
Egypt
3470 Posts |
quote:
Originally posted by echizento
Cleaning coins removes the toning and patina that has been built up over the years. This effects the value of the coin.
On the other hand those of us the collect ancient coins do for a lack of a better term clear our coins, only to remove several thousand years of dirt. Only going as far as removing the crud and not the patina.
Thanks echizento |
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Valued Member
Netherlands
309 Posts |
I am not to fond of cleaning coins myself, but in some situations, they have to be "fixed up" a little, when you find coins using a metal detector, it is most of the time nessesary to clean them, to see what it is in the first place!
there are manny, manny ways to clean a coin, too much to list, but it's also depending on the coin, and the metal, and the faleu of the coin, if cleaning is nessesary at all.
I found some late roman coins with my detector in the past, and I only could tell that it where roman coins After I got a lot of oxidation of it, so.....
Yes, some time's it's to be needed to do, but if posibble.. DON'T!!
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Pillar of the Community
Belgium
2078 Posts |
Hallo Carl long time no see ( lang geleden ) I have some 20 year old krugerrands I sold last week They probably were MS65-MS66 I decided to get rid of them at melt minus 1.5% Some at the dreaded green spots on them ( I think they are 10% copper ) So I could not be bothered to put them in acetone for three days If they had any value at all I would have removed the spots by soaking them in acetone but now the price was fixed anyway Banged up or green or pure they are melt minus 1.5% On the other hand I have one 150 year old king with green spots He went into acetone for three days Not even a microscope can see the bath he took  |
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Pillar of the Community
Belgium
2078 Posts |
Do I clean my coins ? NO It has been 45 years since I cleaned my coins As a 14 year old I used copperpolish to shine my Napoleons with a special rough jewellers chamois rag And I learned my lesson when I got melt minus 5% instead of melt plus 35% |
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Valued Member
Netherlands
309 Posts |
Hello Guust,
glad too be back, it was far out too long ago I was here ;-)
Greetings, Carl
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Pillar of the Community
Belgium
2078 Posts |
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Replies: 33 / Views: 3,170 |
First Page
Posted 12/03/2006 08:19 am
