Same fear here. I set today aside to clean and dress my convertible top. I ordered a 303 convertible top kit and with hose in hand, was ready to go. First I wanted to make sure my top drains were working properly. So, I poured a half liter of water down the passenger side top and it immediately peed out the bottom. Great! Did the same on the drivers side and it was dry as a bone. Added a little water with no results. Dang Nabbit...!. Got the shop vac out with 1/2 inch tube duc taped to the vacuum hose. I sucked the water out of the drivers side. Then put more in with a little dish detergent. Reversed the Vac hose so it now blows and stirred thing around. Started to get a little water coming out the bottom. Did this process of blowing, sucking, and mixing a few times until finally got a good steady stream of water coming out the drivers drain. The cleaning process and clearing the drains along with washing the car turned out to be a day long process. But, hey, the top looks great.....!