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Which household liquid will clean a copper penny the best

Q. Ok I am doing a science fair project on which household liquid will clean a copper penny the best, and vinegar [in bulk on eBay or Amazon] was the best, but I also need to do a research paper and need info. So I was wondering if you could help me?


Jenna S [last name deleted for privacy by Editor]
- Nashville, Tennessee

A. Hi, Jenna.

Please see our FAQ: What Cleans Pennies Best, and I think you'll find exactly what you need. Good luck!

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

A. It sounds to me like you have all the info needed. Simply sit down and write out what you observed. Have you looked up the chemical composition of vinegar? Have you looked up the chemical name of vinegar. Do you know the basic (or acidic) condition of vinegar. Do this with all of your test solutions and then put the data into your paper.

Dan Brewer
chemical process supplier - Gurnee, Illinois


A. Try putting the copper penny into different solutions, such as bleach [adv: bleach/sodium hypochlorite in bulk on eBay or Amazon] (diluted before use!), citric acid [on eBay or Amazon], acetic acid (vinegar), different citrus fruit juices and any other liquids you may find. Ask your mother or father for some help in getting different ones; go to the hardware store and see if they have any liquids for cleaning copper or brass.

[Depending on what grade you are in] Try hydrochloric acid, but be very careful with this as it is very strong; similarly, try sulfuric acid and nitric acid, but again these are very strong and should be handled with great care.

Other solutions could be coca cola/ Pepsi cola, other fizzy drinks, beer (!), cider(!) etc; also try tartaric acid (as used in cooking) and any other possible acids found in cooking. If you can get some rhubarb, cook it up with some water to extract its juices and try that (you can also eat the rhubarb afterwards if you want!, but do not eat the leaves.) Cook up some cabbage (ugh) and try the water after cooking. Will straight tap water do the job? See if sodium carbonate / washing soda [affil links] and sodium bicarbonate have any effect. Compare the difference between the cleaning solutions and also compare them after you have added a few drops (literally 1 or 2 drops) of washing up liquid. Try different concentrations of possible solutions by diluting them with water. See what happens at different temperatures; does the copper clean faster or slower?. Does leaving the experiment in bright daylight have any effect? Do you get any gases coming off the metal?

Science is fun and to enjoy it, you MUST DO the experiments. The important thing about science is that you OBSERVE what is going on. Note everything that happens, no matter how trivial. Once you have got the results of the experiments, trying to understand the results can be the difficult bit!

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

A. Jenna,

When I did this project myself I found out that TacoBell hot and mild sauce worked better then vinegar! The next time you go there ask for a few packets of both mild and hot sauce to try the experiment against vinegar. To do this project against each other time them different time limits and see if it works for you like it did for me.

Gianna M [last name deleted for privacy by Editor]
- Victorville, California

A. Well vinegar does work quite well (I'm doing a science fair project also) but you should also try out Tarn-X tarnish remover [on eBay or Amazon] and Taco Bell hot sauce. Don't leave the coin in Tarn-x too long or it will eat the penny! Good luck!

Ava S [last name deleted for privacy by Editor]
- Fort Collins, Colorado
March 23, 2010

A. I am doing the same project and my dad told me ketchup works best; try it, it just might.

Dominique [last name deleted for privacy by Editor]
- Rosman, North Carolina
September 23, 2010

How to Graph the Cleanliness of Pennies?

Q. 6th grade Science Project. My son's project is to test: "Which liquid removes the copper oxide from the Penny's the best"? His teacher wants a way to measure the results in order to put in a graph. We thought of weighing in grams the results but there does not appear to be enough resolution. The scale weighs in grams and has two decimal places. Any suggestions?

Cheryl Kelly
6th Grade Science Project - Taunton, Massachusetts USA
December 6, 2010

A. Hi, Cheryl.

Your situation is quite common. You have only qualitative data, like one penny is shinier than another, but the teacher wants quantitative data so your son can graph it. You are right that your scale with grams to two decimal places won't offer enough resolution. And the tender age of the student, limited lab equipment at the school, and perhaps chemical paranoia seem to be conspiring to prevent you from obtaining quantitative data.

So take a lesson from TV commercials. They often claim that a product "reduces the appearance of fine lines by 78%" or similar nonsense. How can they possibly put a number on it that way? Here's how: they just make up their own scale.

So find the shiniest new penny you can find and call it 90% bright. Find the grungiest old penny you can, and call it 10% bright (I wouldn't use 100 percent or 0% brightness because it's always possible that you might some day find a brighter or duller penny). Now find a bunch of pennies and rate their brightness as compared to your 90 percent and 10 percent samples. Maybe glue a penny each of 10%, 20%, 40%, 60%, 80% and 90% to your graph as the "control" pennies. Now you clean some pennies and rate them by percentage brightness according to your scale. Voila, you've got numbers that you can graph. You can even paste the cleaned pennies onto the graph at what you claim is their brightness level if you wish. Good luck!


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
December 6, 2010

How to Find Citeable Resources for this project?

I'm doing the same project but I'm in 7th gr. so I don't know exactly what to use ... also I need some sources 3 internet and 2 books, newspaper, etc. PLEASE help it's due ASAP ... Thanks in advance ... (:

*ps sorry for any grammar errors -- I'm typing very fast!

Chantal B [last name deleted for privacy by Editor]
- Waldorf, Maryland, United States
October 12, 2011

Hi, Chantal.

This page mentions a dozen different liquids you can try. Our previously mentioned FAQ is an internet source that should explain it all, and googling will get you two more sites you can cite; but I think the important lesson you are supposed to be learning from this exercise is to slow down and think problems through :-)

If your response to your assignment is to bounce everywhere, "typing very fast", littering as many submittal forms as possible with grammar and spelling errors (we fixed them) and zooming off, unfortunately the lesson is being lost. A visit with the librarian will locate the two books you need. Moreover, there is a reason why libraries are quiet: it's because a quiet environment, as free from distraction as practical, affords an opportunity to think calmly -- an opportunity that is hard to come by in this age of portable music, phones and texting. Please finish your project and report at the library :-)

Good luck!


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
October 13, 2011

Q. This is my first science fair project. Do I use the same concept to see if pineapple,tomato, and orange juice will make a penny shiny? Thank you

olivia h [last name deleted for privacy by Editor]
- elizabethtown, North Carolina, usa
September 7, 2011

A. Hi, Olivia.

We appended your letter to a thread that should answer it for you, but yes, which juices you use does not change the methods.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
September 8, 2011


March 9, 2012

A. Hi, cousin Kathy.

Please see the previously mentioned FAQ we wrote on this subject.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
March 13, 2012

Q. I am doing a Science Fair project, and I am struggling to find a way to make a graph of the cleanliness of a penny. How should I measure it?

Hikari Inaoka
- Pennsylvania, USA
March 29, 2016

A. Hello Hikari. Your research has paid off by getting you to this page. Read my response dated December 6, 2010. Good luck :-)


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
March 2016

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