This is such a simple thing because all I do is remove the label, wash the cup, and then use it. But just in case no one has thought of it, the gum containers made to fit into car cup holders also happen to make the best snack containers ever.
We usually carry a backpack of random stuff for Pike when we travel – snacks, coloring books, stuff to read, etc. – and these things are the BEST. You fill one up with raisins or goldfish crackers, and all of a sudden you have the absolute perfect tupperware that’s airtight and a small enough portion that if the child chooses to inhale the whole thing, they probably aren’t going to puke in your backseat.