The crystalline sponge method facilitates the X-ray structure determination of samples that do not crystallize or are too sparsely available to afford viable crystallization. By including these materials in a metal-organic framework, the structure of the guest molecules can be determined. Some of the inherent difficulties of this method are discussed and the use of Cu K beta radiation is presented as a simple and effective means to improve the quality of the diffraction data that can be obtained from a sponge crystal.