Remove gasket inside keg?

[The Kitten King]

Hi, I'm cleaning out a used anheuser Busch 15.5 gal beer keg (humanely purchased) and this little purple gasket is inside, do I new to remove this and if so how? It's pretty stuck in there, im sure I could pry it out with a little elbow grease but I'm afraid of the glue that may be left.

Thanks all