I mostly foam tube but I have boxes for warm water and for trout flies. I have had boxes with foam to hold the flies and divided boxes where they are just kept in a section of the box. Both work well. Other than the fact they tend to take up more space there is no reason not to have them in a box with trout fiies. Because we accumulate a good many prescriptions bottles, I frequently use them to transport bugs from my bench to a float tube box or to friend.