Will an "canned air" duster leave residue?

No, our dusters do not leave a residue. They contain 100% volatile propellent, which means the chemical completely evaporates. If there is moisture left behind after using duster, that is condensation from the ambient air because the spray cooled the surface. Be aware that many consumer dusters include bitterant to prevent "huffing". That bitterant  can be left behind as a residue, so should be avoided when cleaning sensitive or critical devices. None of our dusters contain bitterant.