If the frames of the grills are plastic, whenever I had grills like that, I'd just spray some mild detergent on them outside and rinse them with the hose, from front and back. After rinsing them real well, I'd just let them air dry and they looked good as new, barring any snags or holes, but your's look good. The older MDF frames you can't get wet, of course. The cabinets look great. If all the drivers are good, the worst may be behind you. I'm amazed the mids are in such good shape. You rarely see them intact.