1960 D penny with weird squiggly lines on it

Suze

Hi, looking to learn what could cause the tiny bubble like lines on the obv of this au penny, I realize it is pretty trashed because of the large, um, brain cloud rot on Abe’s head, but I’d like to learn anyway. Google was totally unhelpful. Thanks for any input!

lilolme

I recalled something like this coming up a couple times before. Here is one thread found from a forum search. There should be one or two more if searched correctly. Not sure this completely answers what it is but it is a start. Read through it as the information changes.

https://forums.collectors.com/discussion/996988/whats-going-on-with-this-lincoln-proof/p1

Greenstang

Never seen that before.
Are the marks raised or incuse?

Suze

@Greenstang said:
Never seen that before.
Are the marks raised or incuse?

I can’t tell - it’s smooth to the touch

JBK

Could there be a layer of glue?