1996 vw jetta leaking antifreeze through air vents?

You probably have a heater hose that has deteriorated right near the connection onto the heater core, or the heater core itself has sprung a leak. You'll need to look first in the engine compartment to make sure it's not near the firewall, then if not, it has to be under the dash. Your next step is to look in your manual for the location of the heater core. Good luck !