Clear, empty, delete database for another import (development)

Hi, we had a user field which has been removed during time. but some users has already filled it. Is there anyway to remove or clear those entries from the database?

the reason I want to remove it, is that It’s annoying some of our old users, as they can’t change the field anymore.

I’ve already tried to explain the problem here:

https://meta.discourse.org/t/removed-user-fileds-are-still-shown-in-user-profile-page/71344?u=pad_pors