DG and Patrick,
Non A/C cars:
Use a prying tool to remove the snap in grills on the kick panels. On the driver's side you will have to remove the parking brake assy. to gain access to the upper 5/16" hex screws holding the kick panel to the body. Two nuts under the hood, a small sheet metal screw above the brake release handle, and a small slide clip to release the cable end and the brake assy. is out (you may also have to remove a ground wire). Remove the hex screws, front sill plate screw and the astro ventilation ball vents to gain access to the lever that operates the vent baffle. Remove the cable end from the lever along with the cable hold-down clamp screw. Now you can pull the kick panels inboard and towards you. This may require some wiggling around to get them out since the vent hole flares out at the end and catches the body opening (save the creative language for later when you go to put them back in). When they're out, you'll notice a thick layer of sealer around the opening. On my car this was pretty stiff, so I removed it and replaced it with 3M strip caulk, but any non-hardening, waterproof sealer will probably work. Just make sure it's applied thick, because all water running down the cowl sides passes over this area and will come into the interior if not sealed.
Now you can use a heater hose attatched to a vacuum cleaner hose as TW suggested to get every last bit of crud out. You can also see if the metal has rusted and if any holes developed. On my convert. the drivers side had a hole the size of half dollar on the rear side of the chamber. Next stop for the water would have been my carpet!
There is no weakened structure here, so I wire brushed, coated with corroless and applied a patch of aluminum with seam sealer. Here is where all this work could be considered worth it because you can assess the damage and deal with it rather than just cleaning it and hopeing for the best by going in from the windshield area with a long hose. Lubricate the vent cables too while you have them out in the open. Before reassembling, now would be a good to pour water into the space to make sure the rockers (and their drain holes) are clear. Reassembly is the reverse of the above, making sure to press hard on the sealed area to insure close contact.
A/C cars:
This is actually easier than non A/C cars (imagine that!) since the plastic kick panels don't have vents in them. You don't have to remove the parking brake assy. First remove the kick panels, (you'll see the phillips screws holding them in) then you must remove the steel block-off panels that are attatched with screws to the openings. The rest is as above. Be sure to seal the steel panels well also.
Hope you don't find much rust,
Rich
