Over the years I had restored many of these old (the originals) 55 series mics also known as the Elvis mic, they were made and popular back in the 50's. The most common things that go in these mics is the silk screen behind the opening fins and the rubber insulator that holds the mics internal component. I would first dis assemble the mic, it's just a few screws. The housings of these mics were aluminum and polish up very nicely, I recommend wrapping the internal mic pick up with paper and use a piece of tape to hold it in place to protect it while work is being done. Then for the silk screen I would use panty hose, don't laugh it makes great material for this purpose, black and red seem to be the most popular colors used. I would painstakingly cut 3 pieces for the front cover one for top, bottom, and middle of the front enclosure and one piece for the rear cover. Using 3M super 77 adhesive I would spray a puddle of it on a piece of card board and with a small paint brush apply the adhesive to the fins at the backside of the enclosure, then stretch and work the panty material into place, this is a bit time consuming and a bit tedious but don't give up if you take your time in applying the pieces you will get great results. As far as the deteriorated isolator I would use weather striping you can get a roll of this at any hardware store just match up the size with the original used. These are great mics for vocals and add a touch of nostalgic class and sound to your band. One thing though these original mics used a plug on the mic end, type Amphenol MC3M they are out of production and not made anymore, if you don't buy one of these mics with a cable you will need to find one, ebay is a good source but be prepared to spend up around $20 for the plug then with a length of cable you can put an xlr plug on the other end. Shure has re-released the 55 series mics so they can be bought new, the new 55''s do not use the Amphenol MC3M plug.