How do you take sub woofers out of the box?

Most qulity systems you will remove the screws around the rim, and pull out. If you have a glass case where the subs are inside the box, you will have to remove the glass, then the speaker. Some cheap ones are glued closed, or made out of plastic. In either of these cases throw it away, the speaker or box arn't worth keeping they where not built to last.