I just changed the heater hoses on a 1997 F150. The easy way to remove the hoses from the heater core, The narrow strap that keeps the clip from letting the hose slide off the core, needs to be cut on both sides thus letting the clips release and letting the hose slide off. The easy way to cut the strap is to take an old screwdriver and sharpen the end, then heat it and use it to melt each end of the strap, do this on both sides of the hose to release the clip. Then the hose will slide off easily.

 

Thanks for the tip!