I have a heirloom Gillette Knack that will not close. I have not used it, but I opened it up to clean it and now it won't close. The tightening collar doesn't seem to be stuck with gunk; it seems like it is not engaging. It will wiggle back & forth (maybe 2-3mm), but the center bar doesn't seem to move at all when I do this. I have checked to make sure there is nothing bent on the doors or plate. I have also tried soaking it in hot water to loosen any crud as well as let it soak in oil. Does anyone have any experience with this or have any ideas or is it now relegated to decoration only? thanks in advance!