Hi guys I found a 1862 penny today it seems to be just dirty and not corroded. Was excited to find my first pre decimal! Kept looking for the kangaroo but it's a bit older than that !!! What's the best way to clean it I'm a bit scared to rub it too hard have been using toothbrush and soap. Is it copper? Btw my 7yo who was losing interest is as keen as mustard now!