Mains hum is often complex and composed of odd harmonics of the mains frequency, making it very difficult to remove or suppress using simple high pass or notch filters. HumRemoveExpress.s2s is a Spike2 version 7 script that you can use offline to strip out much of this residual mains interference, making your data much more presentable and easier to analyse. This video tutorial shows how to use the script to remove mains hum.