My dad gave me his old kd 550 and I love it. It still works great but is desperate need of cleaning. I’ve tried removing the hinged acrylic cover to clean and polish but I cannot get it to come off. I’m sure 35+ years of crud and whatnot have got it stuck. Does anyone have any tricks or anything that might help? I’ve read the manual and saw the way you slide it in to install it but doing the opposite isn’t working. It’s the original smoky looking translucent lid so I’m terrified of breaking it.