This wholly depends on if you're using the SQL database to store values or the NoSQL database because it's on mango unit or a cloud installed setup.

I'd wager you're using the NoSQL system which means you're gonna have to export, open with notepad, copy and paste the data to maintain the correct date-time format (excel likes to screw with it) then filter by the value column.
With all of your filtered values, append the delete value in the final column, save, and reimport values to delete all unwanted values.
Also note you can change your datapoint properties to filter and ignore extreme/unwanted values so they won't go into your system.

Hope this is of some help

Fox

@rectifier I agree, good idea.

@Jared-Wiltshire Sorry to re-open this thread, but with the anonymous user role introduced in v4, does it mean we should be able to define certain pages with anonymous "View Page" permission which allow access of these pages without the need of Mango login?

BR,
Ricardo