I was looking to replace the return jets in my 1977 pool with something you could adjust easier and that won’t crack. I went to remove and noticed that the first one fell out rather than unthread. someone had duct tape it around the portion that fits into the wall. it seems as if it is just a press fit and when it was built they use glue perhaps to keep the returns in place. was this a real thing? How do I remove them if that’s the case? I guess you need to replumb to convert to threaded style? below are a few pictures of the ones I have.