Here it goes. Cracked this AU-50 out a NGC holder (I have a way better AU 58) because the gunk was driving me crazy. Bought a long time ago, and was annoyed with the coin, so it didn't bother me to crack it out. Soaked in mineral oil about two weeks and used fresh rose thorns to remove gunk. Must get new rose thorn if tips is not surper sharp- having a dull end causes you to not be able to get into the crevices on the lettering or wheat lines and you will tend to push harder and could scratch the coin. Worked two to three seperate times on the coin. Put the coins in an Intercept holder with a airtight cutout so the coin doesn't fall down when you apply pressure to the coin (fills the ring when you buy bulk airtites from JP's. They come in a batch of 100 loose airtights). Only try on low value wheats (like maybe 20-50 of them before you try on high value coin). I have done everything backwards and tried on high value coins first:headbang::headbang: I will post with a second post the post rose thorn cleaning. Please don't post til I finish
Part 3 Here's the 11 S with oil removed- you guys be the judge. The oil hid the lighter color on the cheeks and beard in my opinion. Will this coin grade with oil. 100% I guarantee:
Yup, I'd say you did a good job, I don't see nay problems. Im about to post a problem coin I've been working on also...
very nice. i agree it was hiding the color on the cheeks witht he oil now if it grades that way ( with an altered surface) then the TPG's are not doing their job. Maybe John from DLRC can come here and let us know if DLRC grades coin with mineral oil on them. If we dont hear from him I will try to get int ouch with RG. Most interesting. Thanks.
Again, I would state Spock that oil does not chemically alter the surface at all. It preserves it and protects from outside reactive air contaminates: sulfur, chlorine, pollution, etc. For an altered surface there has to be a chemical reaction in which ions, elements are removed, or new unstable products or formed. Verdigris is not a beneficial by product of a chemical interaction of metal and contaminant (sulfur I assume), though it does fill in nasty holes in coins often. Carbon polymers of oil are not reactive with copper, unless under extreme heat which will degrade the oil- I have researched this point, though I am admittedly not a chemist. If Jim or Thad want to jump in
i never said chemically it alters the surface i merely said it alters the surface kind of like makeup if you will. it can hide the color and it can hide nicks hence a coin can get a diff grade. i am also not saying it does not protect- in fact many museums across the world use a form of oil to protect their coins. one has to be very careful with 2 things one the science is always evolving for good or bad two TPG are built on a certain premise and the best way to preserve coins might not be the best way to get a coin graded in all cases
Spock, point well taken. I coat the coins for protection. I partly think TPG's want good coins graded for the bottom line and hopefully for an altruistic belief that graded coins are much less likely to be messed with (have to crack out and people are reluctant to do that). This does preserve coins for future generations which is true and does benefit the numismatic community in my opinion.
yes but look at it this way i have a coin which has lot of lil nicks i put oil on them and they get hidden and the TPG give it a higher grade thats a no no or should be a no no. thats why i wanted john in here to say what his TPG does with it. otherwise everyone in their right mind will apply oil on the coin it will protect the coin and give it a better grade there is no way to beat that.
Very nice!! I have used a similar technique with ancients until I found the thorn was too weak for the job...but I was removing much more gunk and it was more hardened.
Yes, I hear what your saying. If I submit a coin, it has such a thin layer I am not sure how significant it is, but maybe I am wrong there.
I agree that this technique is worth trying. I would also like to know how the oil was removed. Perhaps I missed the post. Also, is this just a techique for copper or will it work on silver and other coins?
I am curious to see how it would come back from the tpg,s. If the pics weren't labeled and in different threads I wonder how many people would say the the coin was cleaned with the gunk still on. So many people jump right on a coin and say its been cleaned and reason that, "you can tell because of the dirt still around the devices". I am guessing that the post cleaned coin would be thought to be original. Just my two cents
Signing up for this thread, I also would like to know how to remove the mineral oil. Also, was the coin totally immersed in the oil, or just coated?
I used isopropyl alcohol (rubbing alcohol)- ran out of acetone. Coin was totally immersed in plastic cup of mineral oil. Patted coin dry after several dippings in alcohol. And yes, I agree people jump all over coins and make bold claims. I have mixed multiple chemicals on low end problem coins, and I'm not even sure what I did and I'm pretty sure no one could have accurately predicted what I did. Mineral oil, then olive oil.then MS 70, heating- etc, just for my own educational purposes. Greg (a certified coin Doc as far as I can tell) on NGC boards has a good post on this, Try this stuff for yourself and come to you own conclusions.