If you've got a Pro subscription, among other nifty features, you can remove the dates from your mashed videos.
On the iOS app
Tap on the "Date/Caption" button on the mashing screen > select the "Hidden" option > tap on the yellow checkmark icon to save the changes. To bring back the dates, repeat the steps but select the "Default" or "Classic" option.
On the Android app
Tap on the "Date Stamp" button on the mashing screen. Tap on it once again to bring the dates back.
