I keep a rag with a bit of thinner on it to wipe up excess. Never had it stick. The only thing I have trouble with in that regard is the quick drying stuff, but that's not this.
Petroleum jelly. Smear a bit on with your finger, then wipe off with a rag. Don't scrub it off, just take off any excess. Works on all kinds of glue bottles too.
Just to be clear, it helps stop the poly (or glue) from adhering to the threads, but any poly on the threads will still act as a mechanical wedge once it dries. So, I'm afraid it isn't a magic cure-all.
Also, just to note, the longer the poly sits, the harder it will get, making the mechanical wedge effect worse over time.
I saw a tip for paint recently that I haven't tried yet, but it might work here too. If you get some painters tape and make a V over the top it acts as a spout and it never gets on the threads
Got something similar, I tested Teflon tape, it's actually dissolving, but I got (don't ask me where I got it from) thin paper tape, I do one layer over the threads, still gotta replace it every 3 or 4 times I open the lid - whatever, works so far for me. Just test some stuff, I'd recommend. Stay away from plastic tape, it could dissolve. Maybe a drop of oil on the threads? I'll try it, it came into my mind right now.