Hello. I'm a newbie after acquiring my Dads Australian half-pennies and Pennies. I have a couple of questions on olive oil cleaning.
1) From a buyer or sellers perspective - will a clean with olive oil and proper animal bristle brush have any impact whatsoever (assuming its done properly). I mean has anyone actually bought or sold a coin that's undergone this type of clean?
2) Is it recommended after the olive oil clean to wash the remaining oil off in plain warm water? ( I don't think so ... but I would like to ask anyway)
Many thanks
For me I wouldn't buy a coin that has had that treatment as it would no
longer be an untouched coin which is what collectors prefer.But if they're
low grade and you dont plan to sell them you can do what you like but by
handling them you always risk doing some sort of damage
Quote from: 'poorgee' pid='42239' dateline='1392847863'I have a couple of questions on olive oil cleaning.
Hello, and welcome aboard. :wavemulticolor:
Cleaning, any cleaning, is generally a bad idea. You can always tell if a coin's been cleaned, and most collectors won't touch them with a bargepole.
That said, there are, as with everything, exceptions.
If a coin needs to be conserved, say because its being destroyed by PVC or a few hundred years at the bottom of the sea, then its necessary to stop the damage progressing. There are a number of techniques, which have been discussed here at some length. Do a search to find them.
Removing surface gunk is generally OK, as long as you don't alter the coin surface. Anything mechanical is abrasive. Any chemical reaction will also alter the surface. If the surface is altered, it will lower or destroy the value of the coin.
Acetone is safe. It won't move verdigris, but it will remove some organic contaminants.
Olive oil needs to be handled with care. If two coins are in contact while submerged in oil, the overlapping area will be ruined, just like these:
(http://fulvio.jovianprojects.com.au/coins/OiledDollars/DSC01269small.jpg)
And oil can take months and months to have any noticeable effect anyway.
WD40/RP7 is safe. As with anything else you try, do not rub the coin, no matter how gently. You will leave tiny scratches (yes, even with a brush) which are visible under magnification.
By all means try these and other techniques on some rubbish coins. Everyone needs to learn for themselves exactly what can and can't be done, and what the results will look like. Make sure you have a decent magnifier or even a USB microscope to check the results.
Do not expect to improve a coin by cleaning. You can't achieve that, no matter what you do. What you can achieve is to stop it degrading further. And the best way to achieve
that is storing it properly in the first place. Again, that's been discussed here at length. Happy reading, and by all means, ask as many questions as you like. :)
Only sound advice I can give you is cleaning coins is BIG NO NO.
Is there a way of removing dirt which you get on some coins that have been in grandad's shed? Has anyone any expereince with those ultrasonic cleaners?
Quote from: 'Nightparrot' pid='42301' dateline='1392897177'Is there a way of removing dirt which you get on some coins that have been in grandad's shed? Has anyone any expereince with those ultrasonic cleaners?
I can't see the point in storing away coins that are covered in grot and suffering from disease such as verdigris, only to sadly find at a later date that they have deteriorated.
Over the years I have had advice on this from a few sources, and have combined various bits and pieces to arrive at a method that suits me. Please note this only applies to circulated coins suffering from mild verdigris or an accumulation of grot in the devices. I have circulated copper coins that have been stored away for about nine years and exhibit no ill effect at this point. Fingers crossed.
Soak in extra virgin olive oil for at least 48 hours, but three or four days is better
Gently use a wooden probe to dislodge particles of grot and verdigris. If the verdigris has not hardened, the olive oil will generally soften it enough to be dislodged fairly easily.
If the verdigris has hardened you're probably wasting your time, but I have had some success by gently tapping away at it with a blunt sewing needle. Make sure the area is coated with a heavy film of olive oil. Very tedious but may be worth it if the coin is a rare one. In any case, an attack of this nature will have seen the verdigris eat into the metal surface by varying degrees.
When finished soak in olive oil for another 24 hours
Dab dry the olive oil with a paper towel. No rubbing
Thoroughly rinse in warm water with a mild mix of detergent. Do this several times, dab drying with a paper towel after each rinse. No rubbing
Thoroughly rinse with demineralised water
Dry with your wifes favourite hair dryer, holding coin between your fingers while wearing cotton gloves.
Quote from: 'autocoupler' pid='42305' dateline='1392911233'a method that suits me.
Probably about the best way to deal with it, when you absolutely feel you need to clean them. The only thing I'd add is a bath in acetone first, to get rid of organics.
Its hard to beat a toothpick and much elbow grease. Surprisingly, mechanical cleaning like this is less damaging than the alternatives.
And yes, if the cancer has taken root, there's nothing you can do, as it will already have eaten into the surface.
Thankyou everyone for your valuable comments.
Quote from: 'Fulvio' pid='42311' dateline='1392912897'Quote from: 'autocoupler' pid='42305' dateline='1392911233'a method that suits me.
The only thing I'd add is a bath in acetone first, to get rid of organics.
Haven't used acetone for this purpose but sounds like a good idea. In your experience does it appear to negatively affect any lustre that may exist.
Quote from: 'autocoupler' pid='42322' dateline='1392937077'Quote from: 'Fulvio' pid='42311' dateline='1392912897'Quote from: 'autocoupler' pid='42305' dateline='1392911233'a method that suits me.
The only thing I'd add is a bath in acetone first, to get rid of organics.
Haven't used acetone for this purpose but sounds like a good idea. In your experience does it appear to negatively affect any lustre that may exist.
Doesnt affect the lustre but doesnt always remove all organic material
Quote from: 'stevo1962' pid='42323' dateline='1392938083'Doesnt affect the lustre but doesnt always remove all organic material
^^^ What he said.
Solvents are all dicey. If they're gentle enough to do no harm, they also aren't very effective. If they'll strip all the gunk off, they'll eat through your workbench and the concrete floor below. :angel:
Nitric acid will remove everything (including most of the metal in the coin -even dissolves glass!).
NOT RECOMMENDED. Definitely not gentle.
Quote from: 'JeffH' pid='42352' dateline='1392962966'NOT RECOMMENDED. Definitely not gentle.
Might be time to go read the
"Things I Won't Work With" chemistry blog again, eh? Some
FUN stuff to be found there, guaranteed to remove all traces of dirt, as well as the coin... and the desk, house, and just about everything else in its way. ;)
Ah, yes; chlorine trifluoride had slipped my mind.
Coin friendly fluids are generally considered to be;
•water
•acetone
•xylene
Any foreign deposit they won't remove from the coin can only then be removed with some damage to the coin.
Olive oil is commonly used to soften crusts on ancient coins (or more modern that have been buried in the ground) to facilitate removal with a toothpick. It is rather slow acting to damage any metal. The theory is that the overall improvement in the coin's appearance is far more than the insignificant degradation from the oil. Why just olive oil rather than, say, canola oil, kerosine, detergent or a host of other things that might have a similar effect I don't know.
I guess you could apply this theory to many reactive substances.
I don't know of anything that removes verdigris faster than it attacks the base metal. The reaction that causes the verdigris has, of course, already attacked the base metal so that damage is irrecoverable! Plenty of proprietary things are sold with the claim of improving the appearance of a coin. I think the main object of these is adding coin to the sellers pocket.
From some experiments I conducted with "Verdi-care" my conclusion is this just masks the appearance of verdigris to some extent by "wetting" it. Rinse the coin in water later and you are back where you started. I have a bin full of green and/or black stained "coppers" labelled as "scrap". I am happy to experiment with them on the basis of nothing to lose but expect also nothing to gain either.
My advice with olive oil is keep it in the kitchen, where it belongs. Maybe it does have an application for softening crusty deposits on coins that have been buried in the ground for years.
Quote from: 'JeffH' pid='42386' dateline='1393004443'•xylene
This one will also kill you. Handle with care.
Well put, Jeff. Especially about the snake oils.
Mind you, I often wonder why we obsess about original condition. Entropy always wins, and one would think any efforts we could employ to delay it would be welcome. Yet any sign of "tampering" destroys the value of our coins. Makes you wonder...
hi. Given the comments regarding water - I did have the thought of just using distilled boiling water (one coin at a time) - just immerse them to loosen /dissolve the organic stuff (no scrubbing just immersion in boiling distilled water) - Any thoughts on if this has a negative impact.
Water won't harm coins and is a very good solvent but, won't remove a lot of the deposits that coins seem to pick up.
My suggestion, for what it is worth, is to soak in warm water with a couple of drops of detergent for a few hours. Then rinse with distilled water and pat dry with some paper toweling or a tissue. Beware brightly coloured detergents -the dies in them could actually stain the coin.
Any tar, chewing gum or similar sticky goo is best removed with a cotton bud and acetone -but be gentle and give time for the solvent to penetrate and soften the gunk. A wooden toothpick is a handy tool for removing the bigger lumps as you go.
Quote from: 'poorgee' pid='42579' dateline='1393209031'immersion in boiling distilled water
Can you imagine the energy bill for months of boiling water? Cos that's how long it would take. ;)
Many thanks all. Appreciate it.
$1 coins don't take kindly to our washing detergent - unless you like your coins multi-coloured! Water only for them.
Pedro
Thanks Pedro - planning on taking to some of my $1 coins and that just hit the spot.
Quote from: 'Pedro' pid='42616' dateline='1393273411'$1 coins don't take kindly to our washing detergent - unless you like your coins multi-coloured! Water only for them.
Pedro
Coins are a bit like the old vinyl records, Once scratched or otherwise damaged they are pretty much wrecked .
If you have a problem coin simply give it away, sell it or put it in the "Far too hard" Bucket and get a replacement :ok:
Once a coin has been attacked by verdigris or PVC it is pretty much Buggered and unless it is a super rare coin isn't worth the effort IMHO.