In this tutorial we'll go step by step on how to delete a mashed video in 1 Second Everyday on our iOS version. There's also a video, link above, that goes step by step through this process also.
Step 1: Go to the reels section
While your viewing your calendar tap on the film reel icon on the top nav. This will take you to all your mashed videos.
Step 2: Select the mashed video
Simply tap the trash icon on whichever video you'd like to delete from your device.
Step 3: Confirm the deletion
Make sure this is the video you want to delete and tap "Delete" giving 1SE permission to delete the file from your device.
You can also delete your mashed videos from the 1SE album in your Photos app.