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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 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 Sdeleted
- 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!

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
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 (diluted before use!), citric acidamazoninfo, 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 sulphuric 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 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
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 Mdeleted
- Victorville, California

March 23, 2010

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

Ava Sdeleted
- Fort Collins, Colorado

September 23, 2010

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

- Rosman, North Carolina

How to Graph the Results?

December 6, 2010

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: you create your own scale.

Find the shiniest new penny you can find and call it 90 percent bright. Find the grungiest old penny you can, and call it 10 percent bright (I wouldn't use 100 percent and zero percent brightness because it's always possible that you might later find a brighter or duller penny). Now find a bunch of pennies of roughly equal dullness. Now rate them as 20% bright or 40%, or whatever number you feel is good. Keep a couple aside as the control pennies, and now you clean the pennies and rate them by percentage brightness according to your scale. Voila, you've got numbers that you can graph. Good luck!


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

How to Find Citeable Resources for this project?

October 12, 2011

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 Bdeleted
- Waldorf, Maryland, United States

October 13, 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 an 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 zoom 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 try planning your project and report at the library :-)

Good luck!


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

September 7, 2011appended

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 hdeleted
- elizabethtown, North Carolina, usa

September 8, 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.


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

March 9, 2012appended



March 13, 2012

A. Hi, cousin Kathy.

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


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey
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