Ok, I have been making my kids a penny collection, nothing fancy, just good shape pennies and as many years as I can gather together. One method I used years ago when I was *cough* a teenager was a soft pencil eraser. First of all, I was always told not to clean anything if I don't know the value prior so if you have something valuable or don't want to chance cleaning, I wouldn't do this. Anyway, I simply take a large eraser or pencil eraser and clean up the penny or coin. Some erasers are abrasive and you may not want to use one of those, just a soft basic eraser and not the cheap-o erasers that are hardened, that just smears.
You should end up with a shiny coin. I do this on metals where I want to know the date or make but don't want to ruin the object so I just lightly take the eraser a bit over the stamp. Once again, if for total value of the object, I wouldn't do this but just for keepsake, works good.
Paul
EDIT: If you want a REALLY shiny penny, I use white distilled vinegar and a fair amount of salt in a cup, let the coin set for 5 min. If really bad, scrub the penny gently with salt in the vinegar, rinse good, dry off immediately, then take a soft eraser to it. It will look like new. Once again, DON'T do this if you feel it may be worth anything.
You should end up with a shiny coin. I do this on metals where I want to know the date or make but don't want to ruin the object so I just lightly take the eraser a bit over the stamp. Once again, if for total value of the object, I wouldn't do this but just for keepsake, works good.
Paul
EDIT: If you want a REALLY shiny penny, I use white distilled vinegar and a fair amount of salt in a cup, let the coin set for 5 min. If really bad, scrub the penny gently with salt in the vinegar, rinse good, dry off immediately, then take a soft eraser to it. It will look like new. Once again, DON'T do this if you feel it may be worth anything.