interior leak!!!
there is really no easy way but, in the past on all of my non air cars, i took the vent box out from under the dash. i reached up into the cowl and got what i could by hand. then i open the door and look up inside the a-pillar and locate the drain hole for the cowl. i go find a coat hanger that is plastic covered so i don't scratch things up too bad, i put the appropriate bend in the wire and start digging. i try to push as much in to the vent hole and get it by hand, dry. then once i have it opened up some i run water in through the cowl opening and rod out the drain, wet. it has been my experience that if i get the water flowing out the drain, the cowl quits leaking on my feet! good luck and keep us posted on your progress.