You should know that you should never clean coins that may have collectible value. Even though the cleaning makes them look "shinier," such cleaning removes most or all collectible value. As strange as it may seem to those who aren't numismatists, brown or "toned" coins can be more valuable, because cleaning removes some of the original material, and can leave marks that look bad under standard 10x magnification.
I have seen coins cleaned with many household items and experimented with some myself. In one collection I purchased, the collector had even made notes of what he had cleaned various coins with and when. Although several different products will produce a bright coin, in almost every case within a few months or years the coin will look worse than it did before the cleaning.
Don't clean a penny unless your a expert at cleaning pennies. I did it when I was 10 and they still look awful. So take my advice. They will look better if you don't do it. Good luck on everything.