Being curious what the new cent would look like brown and not wanting to wait for a couple years, I put this one out on the deck back in April. It was laying flat on the railing in the full weather. I had forgotten about it untill today and was surprised it's still not fully brown. It also developed some colors, probably from the wood or deck stain. Well back outside it goes. I'll check it again next spring.
I flipped it a couple times after I first put it out but for the last 5 months or so it was shield side up. For some reason the obverse wouldn't upload the first the time.
I don't think Zincolns and the moisture in the ground mix very well, i think they rot fairly quickly, but thanks for the suggestion.
Thanks for the complements on the pics RZ and Krispy. As far as the sulfer envelope, I wasn't trying for a monster toner, I just wanted it to get a nice brown copper patina.
Based on you experiment, I decided to put some out yesterday too to see what happens in moderate fall/winter weather exposure mixed with city air, near a busy expressway, that includes sea air but no prolonged direct sun. They're laid out on a plastic tray: two 2010s, four 2009s (two log cabins and two professional life). One of each coin face up, and face down. It would be more 'expensive' but not that much really, to consider the experiment on the 95% composition cent coins that were issued last year too.
Try getting some yellow envelopes, (contains sulphur), moisten lightly, put a penny in it and put them in an oven at about 200 degrees. Pull out every half hour, remoisten envelope, and repeat. This will add toning. Keep doing this enough and the coin will turn brown. Oldest trick in the book. Btw I don't think the OP coin picked up anything from the deck, this is just toning. Its a little harder to change from red to brown than people realize, otherwise there would not exist any red large cents.
"just toning" or environmental damage from intentional prolonged exposure to the elements? This example is above and beyond the general atmosphere and/or storage conditions that effect and cause toning naturally over the long term. Could prove an interesting grading submission test to further this experiment.
I've seen a few brown ones come through circulation. I'll pull the next one I see. Idk how they got that way so fast but I'll post pics next time I find one.