posted 09-30-2010 05:07 AM
Well probably there are also some collectors out there who owned a coin in a not really "mint" condition or even more worse. So this guide should be like a tutorial and hopefully there will be some more tricks and tips how to "pimp" a recently owned coin. So feel free to add your guides.
I'm presenting some "how to's" as I did it with several of my coins. Any ideas are welcome.
Lesson 1: Polishing
Some coins, especially aluminium alloy ones like the MFA Apollo 8, Enterprise, Skylab, ASTP... whatever... have a very "tender" appearence. So most of these coins I bought had scratches and where just dulled. One option to slick up these coins is normal toothpaste and a soft tissue. Just gently polish the coin and you'll see the medal shines again. For bigger, deeper scratches use silver polish. First drop a little bit of water onto the coin, take the silver polish and also a fine and soft polish tissue. Just polish such bland coins very gently. If you push to hard you might destroy the embossing. So handle everytime with care.
Lesson 2: Brighten it up
Just take an old copper coin and you'll see the coin got dark due oxidation and dirt and use. Also some bronze coins get darker after a time. Now here's a simple trick to bring back the old shine without any chemicals or agressive methods.
Step 1: Clean the coin with a wet tissue
Step 2: Take a full spoon of normal salt (you'll probably find it in the kitchen) and place the salt onto the coins side you want to bleach.
Step 3: Get a fresh citron, cut it in the middle
Step 4: Now Press the citron and drop some citron juice onto the "salted" coin.
Now, you'll have a natural bleach effect. The acid of the citron in combination with the salt dislodges the oxidaive layer. The coin gets back its fresh brightness.
You can repeat this bleaching several times if you want to light up a bronze coin.
Here is an image of my framed STS-88 MFA. I made this bleaching several times and now the coin "glows" from inside out. You can see that the inner point is lighter and gets darker to the outer diameter:
Gently wash the salt away and dry it with a wet tissue. You also can seal the coin with isopropanol, special alcohol you get in every drug store or even at the pharmacy.
Before you bright up your space flown coin, or collective coin, try it out on a normal dollar, copper coin or any else coin you'll find in your wallet.
Lesson 3: Highlighting
So some coins are made of darker metal or they got a dark coating. Therefore the embossing just gets lost while you take a look from a farther distance. So you can accent the embossing of the coin. Now, for this purpose you need also metal polish, an eraser and a soft tissue. Take some metal polish and add it onto the coin. Now take the eraser and place it with the flat side onto the coin. Make gently circulating moves with the eraser on the coin. The metal polish between the eraser an the coin just highlights the embossing.
The darker ground of the coin won't be touched. So you just polish the increased lettering.
Clean up the coin with an middle hard teeth brush.
Here is an image of my 50th anniversary NASA coin. Bevor polishing it just had a simple embossing. Now the lettering raises from the rest of the coin.
Now with this option you also remove the coating. You can seal the coin with a clear, transparent varnish. Bevor varnishing use the isopropanol for cleaning it up again and wait until the coin is dry again.
Before you want to highlight and accent a coin try it out on another one. Once you've removed to much coating from the coin ist not possible to make the highlighted areas dark again.
Bronze coins can be darken with high concentrated vinegar. The vinegar benefits a new oxidation. But this takes also a long time.
Editor's note: Threads merged.