T-shirt Quilt Interfacing too stiff
Hello everyone. I'm new here and so I apologize in advance if I'm doing this wrong, or for whatever mistakes I may possibly make in posting this question. My mom, who is a beginner sewer, made a t-shirt quilt. She asked me to finish it for her and I agreed. I had never seen it before, so when she dropped it off I almost died. She used very stiff interfacing on the entire thing. She says she thinks she used Pellon 809 fusible interfacing. What can I do to make this less stiff? Would washing and drying it a million times work? I don't know what to do. I read some stuff online where people suggested re-ironing it to get the glue soft and then trying to peel it off. But that seems very time consuming and it's also been sewed into the seams and so even those are stiff. These shirts were my grandmother's, and are irreplaceable. Is there any way at all to save this quilt? Any tips are greatly appreciated.