[twindman]

If you have the older style of screws holding the coroplast on you can just unscrew some of them near the handle and drop it down a couple of inches and take a look inside with a flashlight. If everything looks ok, maybe figure out a way to blow some hot air inside the opening then - not sure what you can use for this tho!
If you have the newer attachment method of rivets, you can pry them off (look for other threads about coroplast) and try the above also.