Skip to main content

‘Rocket’ removes residue from blanks

Coinage blanks go through several processes that include lubricants. How are these oils, etc., removed so the coins don’t turn out to be greasy to the touch?

Coin blanks are put through what has been nicknamed “rocket” where hot air is blasted to remove oils and water residue. Not all blanks are washed.


How does the current U.S. government shutdown affect the U.S. Mint?

The Internal Revenue Service is the only institution under the authority of the U.S. Treasury Department that was impacted by the late 2018 partial government shutdown brought about by a lack of funding approval by Congress and the President.

What does someone mean when they say the grade of a coin can be impacted by type-specific factors?

Type in this case means what design is being used. Some design types strike up better than others. The design elements on a coin, the metal composition (and therefore the hardness of the blank), the wear of a die, and the efficiency of the coining presses available at a specific mint may each impact the appearance.

Can you give me examples of type-specific factors that impact the grade of a coin?

A Full Head Standing Liberty quarter, a Full Bands Mercury dime, and a Full Bell Lines Franklin half dollar are examples of where the design, the quality and wear on a die, and even the pressure at which the coin images were impressed become factors in the grade of a coin at the time the coin is produced. Should the coin have an unusually high relief, such as the date area on 1916 to 1924 Standing Liberty quarters, this will impact the grade of coins that have circulated.

How thick is the electroplated metal that is applied to the surface of some coins?

Electroplating is applied in single or in multiple layers depending on the composition of the host blank, the metal to be applied using this technique, and the efficiency of the cleaning process to which the blanks were subjected prior to the plating process.

What steps are involved in the electroplating process?

The coinage blanks are cleaned with specific acids depending on the metals involved being applied to the surface. This ensures better adhesion of the metal to be plated. The metal particles contained in the solution had been adhering to the cathode. The blanks become the replacement for that cathode when an electrical current is passed through this solution.

E-mail inquiries only. Do not send letters in the mail. Send to Because of space limitations, we are unable to publish all questions.

This article was originally printed in Numismatic News. >> Subscribe today.

If you like what you've read here, we invite you to visit our online bookstore to learn more about Standard Catalog of World Coins, 1801-1900.

Learn more >>>

 SCWC 1801-1900 is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to and affiliated websites.