On Ultimaker S5 printers, you can download our Copper Filamet profile. We do not recommend using official Ultimaker Print Cores with our materials. The AA cores use bronze nozzles, which will wear away after a couple of prints. CC cores have ruby tips. They are very hard, but they jam up easily. Instead, we recommend 3D Solex Print Cores. They have hardened nozzles and they are easily replaced and switched out for a different size. To use 3D Solex Print Cores, you can either select AA 0.4mm as the print core and change the \\"Line Width\\" to the nozzle size, or change it to the Print Core that matches the nozzle size that you are using. The second option requires you to dismiss an error on the printer when you print because the print core installed in the printer will not match what you chose in Cura. 3D Solex Print Cores are set to 0.4mm in software. If you end up with a jam, the best way to clear it is to do cold pulls with PLA. After a few, when it starts to look like it is clearing, push a nozzle cleaning needle into the nozzle. Continue cold pulls until you see the jammed filament is not on the PLA you are using to clean. Reload the filament and start printing again.