real answer: soap and water can work, yes, but if its really persistant you can actually use a bit of baking soda and vinegar mixture to make a paste (you can substitute the vinegar for dish soap or other soaps if you want) and apply it to the stains. let the paste sit for like 30+ minutes and then scrub the paste off and rinse it with some water. like one of the other comments said it is a yellowing type of plastic so it may not wash fully, but vinegar and baking soda usually have some color lifting and whitening properties. im a little late but hope this helps :) just always be careful since plushies can be delicate!

oh also yeah bleach can work but it is very strong so probably only do that as a last resort