I picked up a pair of Marantz Imperial 7 speakers with the 4 ohm phenolic ring tweeters. They test good, but both have broken dust caps and tears in the paper cones. I carefully removed the dust caps (pretty sure I have replacements on hand) and the voice coils look fine. Is there anything I can glue over the cones that will seal them and at least look presentable (the backs of these are sealed so repair from the back is not possible)? I’ve heard where someone uses nylon stocking material with a dilute glue solution that is reapplied over the nylon when dry….