Instructions
Turn the PS1 off. Insert the Memory Card with the saves you want to delete into either of the Memory Card ports on the front of the PS1. Open the disc tray and remove any disc that is inside.
Turn the PS1 on.
Select "Memory Card" from the main menu. All of the files on the card will be displayed on screen. Use the directional pad on the PS1 controller to move to the save you want to delete. Highlight the save, press the "X" button and select "Delete" to delete the save. Repeat this process as necessary.