what container is it in? how air sensitive is it? Can you not flame dry a flask, pop the septum long enough to dump your solid in, then cap the flask again? Is it that sensitive? What happens to it? pyrophoric, hygroscopic, deliquescent?
If it's in a container with a septum already, then just syringe in solvent (with a venting needle and a positive pressure of inert gas). If it's in a screw-top bottle, then the manufacturers must hate you, or expect you to use it in a glove box. In which case some inorganic lab probably has a glove box with solvent in it.
My guess is that you'll be able to do the 'dump out really quick' method. otherwise we'll need more information.