How would you suggest I clean a plastic ice bucket?!

That's pretty cool! The orange color sort of screams early 70's though and the fact that it's plastic inside and out makes me think it's a little later than early 60's!. They were still using a lot of metal and aluminum for ice buckets and things made from all plastic were still kind of expensive!.
I would clean it by letting some hot water and a little bleach sit in it for about 20 minutes or so!. That should remove the staining!. You could squirt some dishwashing liquid in for good measure while it soaks!.
Rinse it out a few times, dry thoroughly with a lint free cloth and fill with ice!Www@FoodAQ@Com

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very carefully as you don't want to scratch it and plastic is soft!. You could use a smooth cream cleanser even tooth paste may work!. Another good method is the new micro sponges but they do disintegrate with rubbing and only require rinsing in water---good for cleaning walls ,doors and kitchen benches and cupboards so buy a few as very useful for stains!. Good luck and treat it carefully!.Www@FoodAQ@Com

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there is an traditional method for cleaning of such utensils with the help of lemon (supposed to rub the surface with it)!.
but better to try first with any cleaning powder and then to leave the utensil for a night!.Www@FoodAQ@Com

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If dishwashing liquid doesn't work, I would try a Mr!. Clean magic eraser, and if that doesn't work, good old fashioned bleach and hot water!.Www@FoodAQ@Com

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hmmm!.!.
if soap and hot water doesnt work!.
then try brillo pads and or bleach and use a little elbow grease!.
that should be all it really takes!.Www@FoodAQ@Com

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