Clear it? Do you mean how to make it so you can see everything in the gallery?
I've provided a file that will fill out the gallery - check the post below (read all of it as it explains how to use the "persistent" file). The "persistent.zip" file is attached to the post at the bottom. Just unzip the file into your "saves" folder (replace your current "persistent" file).
Serenity Chapter 1: Version 1.4 (update) (EDITED) | N2TheFire on Patreon
I have no idea why you would want to do such a thing. And I only know how to do it on the Windows PC version. I am not responsible if you break your PC by doing the wrong things here, so make sure you're going into the right folders.
Make sure you're not running the game.
Go into the game 'saves' folder: (Serenity-1.4-pc/game/saves)
Rename the file named "persistent" to anything: (ie: persistentOLD) - note that it does not have an extension
Now go to your appdata folder (C:/users/<yourusername>/AppData/Renpy/Serenity-1597420954)
Inside that folder, rename the "persistent" file the same way you did above.
Start your game... the gallery should be all locked again.