How to remove remnants of neoprene ring?

Ok, ripped out a (new!) Yorkville because it was defective. I had to yank really hard until the neoprene ring finally split in two.

Now, how do I remove the neoprene remnants stuck to the ABS pipe? Alcohol and stuff doesn't seem to cut it in this case.

Regards, Joerg.

Ok, alcohol does seem to work. A little. Lots and lots of rubbing and gradually it is coming off.

Regards, Joerg.