Hello, this is my first post, so I hope I am posting it correctly. I recently aqquired this very nice Primus 71 that I believe is from the 1930's (no date code). I would like to unscrew the pipe in order to have a look at the wick. However it is very stuck, and I can see that someone before me has tried to unscrew it, as the pipe is a bit "crushed". How should I proceed? I attach some pictures of it from the ad. Thank you in advance.