What do you think? I've tried to duplicate this pattern on other pennies using various household items, including "torch" lighters....I can't duplicate it........
Being an electrician for about 20 years now I've seen a lot of weired stuff. I think I've seen this mark several times in the past but I'm not 100% sure about the one you have. In older homes and buildings that still have the old fuse boxes people put pennies in under a fuse that keeps popping. It's been done for years. This keeps it from blowing out because it's a direct connection and by-passes the fuse. DON'T EVER DO THIS!!! The fuse is blowing because the circuit is overloaded. Fuses are designed to pop if overloaded. You will be sorry sooner or later if you try this. PLEASE DON'T DO IT!!! I'm not trying to pass on bad ideas here. This is just my opinion on the marks.
Another possibility to this is incomplete plating. Remember, these are copper coated zinc pennies, so the plating attempt could have been done incorrectly. Just a thought