You don't like brushing your teeth with a dirty toothbrush ? Well, guess what, the american soldiers of ww2 don't too! 
Here is an example of a nice item delivered to each G.I. to keep your toothbrush clean in a dusty battlefield. 
This is the early type and would be available later in PX shops. It is a better quality than the normal issued type. More details and also some holes to allow the toothbrush to dry properly. 
Rare item to find.