How to disconnect the heater hoses from the firewall?

I am currently trying to replace the heater core in my 97 Buick LeSabre. I realized that I can't reach the clamps to release the hoses from the firewall. There is no space to get my hands down there with a wrench to loosen the hoses. I was wondering if there is an easy way to get the hoses off so I can get the heater core out? Also, do I have to get new clamps once they are removed because they are the spring clamps and not the screw clamps? Thanks!