Could be old adhesive. Does not look like any kind of Mint Error that I know of. More like Environmental Damage.
Makes you look twice for sure! I would say glue as well. Something was stuck on the obverse for a while to keep part of it in a red state while the other is brown.
Yes, it is a well worn, 1960 Large Date from Philly. I would still try to get all the organic debris off, but with the condition it is in there is almost nothing you can do to turn it into a keeper. By clearing off the debris you might be able to check it for minor doubling...very few people will want a minor doubled cent with this much problem but at least you would know...Spark
My opinion of coins found like this. This was probably in a coin book at one time and held in place by tape, use Acetone-let it sit for a couple days, wash off and take a loop to it, I am thinking all your doubling will disappear-chuck
