You can certainly try to "PB Blaster and toothbrush" the clamps...but by the looks of them they arent gonna budge! You can either;(and I have both)dremel them off(cutting wheel) or use a pair of wire snips and just kinda work the snips under the tightening part of the clamp and then just snip the clamp off. More importantly!!! On all 3 I have done there was sufficient excess slack in the fuel line and return that I just used a razor and cut the hose right where the nipple from the sendor unit ended. Then you can deal with the clamps still on the sendor with the sendor on a bench at eye level...MUCH easier. The fuel filler hose(big un)clamp you will have do "in situ".