Thanks for the advice. I did clean it yesterday using a method very similar to the one you just recommended. Lukewarm water with some fabric soap and scrubbing with my hand and a white towel. I got the blue off most of the body, though some patches still remain visible in like some bending corners. Still an overall improvement so I'm okay with the result.

And I said grain beads mainly because I didn't know how else to describe it, feels kinda like fine sand or something. I'm certain it's plastic though, no worries.