Problem solved, sort of. After researching the subject on this forum and elsewhere the 'gum' is simply a weatherproofing that protects the threads. So it's not really structural. Applying a latex coating is all that's needed. This is one recommended product and what I used. Just brushed it on. 2 coats in those areas that were really bare. We'll see how they hold up. I've also got some Jumbo Jims incoming and will wait to go tubeless when I eventually mount those.