Can Ketchup Clean a Penny? #sciencegoals

Squeaks loves collecting shiny pennies, but sometimes he finds one that's sort of grimy and dull. Lucky for him, Jessi knows a really cool science trick to clean up those tarnished pennies!
----------
Love SciShow Kids and want to help support it? Become a patron on Patreon:
https://www.patreon.com/scishowkids
----------
Looking for SciShow elsewhere on the internet?
Facebook: http://www.facebook.com/scishow
Twitter: http://www.twitter.com/scishow
Tumblr: http://scishow.tumblr.com
Instagram: http://instagram.com/thescishow

SOURCES:
http://buggyandbuddy.com/science-for-kids-make-a-penny-turn-green/
https://www.exploratorium.edu/science_explorer/copper_caper.html
http://playfullearning.net/2012/06/six-ways-to-clean-a-penny-a-simple-science-experiment/
https://chemistry.stackexchange.com/questions/2765/why-is-salt-needed-when-using-vinegar-to-clean-pennies
http://cleaning.lovetoknow.com/Penny_Cleaning_Science
http://applenetwork.us/experiments/VinegarPennies.html
https://water.usgs.gov/edu/ph.html