Sorry, I meant to say: = '(nothing between the quotes)';" as opposed to = '-1';"

I guess I now have it set to -1 because when I ran that query again earlier for a second time it wouldn't change any rows, even though in the CP users still show up with a blank setting.

So how can I blank out the setting now? Is it safe to run a query with just '' to wipe out whatever setting I created?