How do you take coggs off back wheel of my bicycle

If one wants to take off the whole freewheel, one usually buys a freewheel removal tool that matches the brand of freewheel, takes off the wheel, takes out the quick release skewer, puts the removal tool onto the freewheel, uses the quick release skewer (lightly screwed on) to keep the tool from slipping off, then clamps the removal tool into a well-mounted vice and unscrews the freewheel by grasping the wheel rim. They usually come off before something breaks... but occasionally not if they've been on for a long time, since pedaling tightens them... and tightens them... ;-)
- Roy