https://www.reddit.com/r/woahdude/comments/dg7xpp/the_neon_at_my_local_brewery_does_this/
@mudkripple @DougCim53 said : Most neon signs don’t have actually neon anymore (or at least not pure neon) as its much too rare and expensive. Instead they mix argon (another noble gas that’s much cheaper) with other stuff to make different colors. A lot of the “neon” signs I see today look like CFLs, like they just made a normal white CFL bulb and then covered the outside of the (opaque white) tube with some translucent plastic or something.
origin - https://www.pipiscrew.com/?p=15469 the-neon-at-my-local-brewery-does-this