I did the same with these pans too. Though I didn’t need an angle grinder. A day or two in a trash bag marinating in oven cleaner, then some steel wool and elbow grease. That’s why I call them my babies, they are antique pans that sadly had gotten rusty and I gave them new life. They were my mom’s, and before her, her great-grandma’s pans (and maybe someone else’s before then but we, the family, have lost track).