X-ray diffraction experiment requires precise positioning of the sample in the X-ray beam. For protein crystals, this is done almost exclusively by crystallography loops. In this mini-workshop, we will introduce the problematics of loop handling from the initial choice of suitable loops, through crystal fishing, up to cleaning after the experiment and replacement in case of loop damage. Due to the hands-on nature of the mini-workshop, the number of participants is limited by the available space in the laboratory