Sounds to me like it is mice or rat droppings. Termite droppings are dry pellets that resemble sand and don't usually stick to anything. Mice and rats love all things cardboard and paper and will make an absolute mess. Their droppings and urine will stick to everything and can carry pathogens..
1. Remove everything from the boxes and let it air out for a few days. this will allow things to dry out and will help with the odor. Latex gloves are a must! Wash your hands thoroughly after handling.
2. Use a shop vac and try to remove all the loose debris. Use a soft 1" wide paint brush to get in to all the "nooks and crannies". Again,Latex gloves are a must! Wash your hands thoroughly after handling.
3. Carefully disassemble and clean everything using normal methods as discussed here in the forum before.
I have had excellent results removing mice/rat droppings with dawn in warm soapy water gently a soft toothbrush. Just be careful around rubber stamped lettering and decals on the older trains.
Hope this helps!
Ricky
