mel try heating up a little peroxide, a couple seconds in microwave and drop coin in and let soak. it will bubble awhile, after 20 min try picking gunk off with a toothpic, repeat if this helps. after i get it as clean as i think i can i put a little mineral oil on it. i may be wrong but like most ih pennies the 2 center may also be bronze.
Awesome find buddy, Im with Tana on keeping it in olive oil. I have coins that have been in olive oil for six months, I rub them down about every two weeks.