What often works is the repeat swallowing of boluses of bread without the crust or cereals such as thick Cream
of Wheat. For liquids, the more viscous, semi-
liquid, the better as it is more capable
of carrying the plastic along than thin liquids. Examples of this would be milkshakes or yogurt.
However, if this material has not passed in 24 to 48 hours, you should seek medical advice, probably best from a gastroenterologist.