When liquids (aqueous solution, buffer, etc.) have been soiled by “nanos” (nanotubes, nanocrystals, nanopowder), the latter will be collected in identified containers and stored in a suitable place (under a hood, in a glove box, in a chemical cabinet, etc.). These wastes should not be mixed with other chemical waste liquids of the premises and containers will be placed in specific retention bins. Waste contaminated with heavy metals will be distinguished from those that are not.