To delete Selected items ...using the Casio WK internal program:
1. Press the 'Transpose' button.
2. Down cursor to the 'delSMF?' display. That will remove SMF files, by pressing 'yes' ...then using the 'yes/no' buttons to select the actual SMF to delete.
3. If you right cursor...you will see the display show 'DelRhy?'...another right cursor shows 'DelTone?' (this gives you access to delete the tones in memory slots 700 to 803....which are all the 'wave' sample tones). Again, you use the 'yes/no' buttons to select the thing to delete.
To wipe all the memory clean...press the 'Transpose' button...then, cursor down to
'InitMix?'. Right cursor to 'InitSys?'...press yes...and you will have cleaned the memory (factory reset...all settings cleared)
You can also use the Casio Data Management software to remove any file.
1. Select the keyboard tab (right side)...and in the file type prompt (upper left side..the white box drop down)
2. Select the type of file to display. Press the 'refresh...blue circle arrow..right side'
3.Select the actual file to remove (by highlighting it)...and press the 'red X'
4. The Casio software will remove the file (If you are connected to the computer with midi cables)