Flame King 1lb refillable propane

[AlphaTea]

Well, today I filled up 17 and a half bottles off of a newly filled 20lb tank. I may have been boned on that tank fill then again, some of the loss could have been due to having to vent each bottle to ensure a proper fill.
The plastic caps fit on pretty snug, so I dont think the threads will rust. Actually Im thinking the threads are brass, so they wont rust anyway.
I think Im gonna go with your thought Domeguy, Im gonna do it half and half, and when I fill them next time look to see if it makes any difference.

[Illini Warrior]

most of the disposable 1lbers are all steel - and the threads will rust in time - when I was a kid and kept using the same bottles over & over -I'd brush down the threads about mid camping season - can't use any lub and the Midwest humidity would kick in the rust ....