What Is This?

Hi.

I see this ever so constantly on the reverse sides of late date large cents, and I don't have a clue of what it is. Some cases are worse than others.

You see that little gash above the N in "one"? There is some sort of clear white stuff on it. Almost looks like superglue.

I see it all the time while browsing ebay for these particular coins. Often, as with this example, on an otherwise problem free coin.

Is it glue? An attempted repair? Some sort of corrosion? Any ideas?

Thanks.