Back in 2014, I did as Gerald suggested in his post.
Not exactly a milk bottle cap but a Solan de Cabras mineral water one. This one:
I cut the bottle neck, adjusted it to the top end of my fishing rod without the top cap, I wrapped the cut bottle neck and the fishing rod end with electrical tape as necessary for a perfect fit and it’s been there for 5 years now without needing any further repair or maintenance. I have a threaded cap now and it’s a lot better than the original press-fit cap.
73,
Guru