Open your audio editing program and look for an "Effect," "Audio Processing" or "Audio Editing" menu. Select this menu and then select the option to use your high-pass filter.
Find the options in the high-pass filter menu. There are typically three options: rolloff, filter quality and cutoff frequency. Look for the box that says cutoff frequency and enter in the number 60. This will attenuate any frequencies below 60 hertz.
Press "OK" to finalize and allow the audio-editing program to attenuate the frequencies. Listen to the audio playback. If the tape hiss remains, complete this process again, increasing the cutoff frequency by 5 hertz at a time.